Diversions, Mechanical Diversions (Part 2 of 3)

This post is the second part in a three part series about some of the major causes of diversions. In part one I talked about weather diversions.  In this part the focus will be mechanical diversions. Just like part one I will start off with a small scenario and then talk about procedures regarding mechanical diversions.

Imagine you are on a flight and everything is cruising normally.  All of a sudden it gets quieter and you feel that the aircraft is slowing down and turning. After a few minutes the captain gets on the intercom and says: “Ladies and Gentlemen, sorry to tell you but we are going to have to stop short of our destination. We lost all oil pressure and quantity in the right engine and we have shut it down to prevent any further damage. As you probably can tell we just descended and we turning away from Chicago towards Cleveland to land there. Airplanes are made to fly on one engine and the copilot and I are trained in handling the situation. We will be on the ground in about 15 minutes. Just to let you know, when we get on the ground there will be emergency equipment out to meet us on the runway. I requested this just as a precaution just in the very unlucky event that anything should happen. Again, I’m very sorry about this but will be on the ground in 15 minutes. Flight attendants please prepare the cabin.”

A Turkish Airlines B777-300 experiences a compressor stall on climb out of Tokyo-Narita airport.

A Turkish Airlines B777-300 experiences a compressor stall on climb out of Tokyo-Narita airport.


The diversion I just described above is very rare. Jet engines are very reliable pieces of equipment and they are well maintained. Engines also get changed after a certain amount of hours so they do not fail enroute like this one, but all mechanical things can fail.

I have had to dispatch a scenario just like the one above. It was an afternoon shift later in the evening and the crew called up on the radio.  They had lost all oil quantity and pressure in the right engine and had shut it down. They were right over the top of Norfolk, Virginia. I told the crew that they needed to divert to Norfolk. I briefly told them the weather was good and I would be contacting the local station to let them know that they were coming. It took the flight about 15 minutes to get on the ground. Once on the ground the captain called me, he said that their engine had blown oil all over the place and it was pooling on the ramp below the engine. Obviously, this was a major mechanical failure of that engine. I found out the next day that the engine blew a seal.

Engine failures are so rare that an airline pilot can go his whole career without actually having an engine failure. This has been my only engine failure in the 8 years I’ve been working as a flight dispatcher.  Other dispatchers in my office have worked over 30 years and never had an engine failure on any of their flights. While an engine failure is the most obvious reason to divert an airplane, there are some other subtle things that could cause an airplane to divert for maintenance as well.  Some of these could be issues with the fuel pump, air-conditioning packs, potable water issues and several others.  These concerns, while not directly impacting passenger safety, may affect the ability of the aircraft to proceed to its next destination.  It is always wise to address the issue before it becomes a matter of safety or canceling flights.

Mechanical problems happen often on an airplane but they are usually very minor and only the pilots and dispatchers know about them. There is a book on every airplane that gives detailed instructions on the procedures the pilots need to follow in case any of the systems has a mechanical failure. My airline calls this book the Quick Reference Handbook or QRH. Some airlines might call it by a different name but the purpose is the same. Most of these mechanical failures just require the crew to fly the aircraft in a different configuration and continue to the destination without any problems. Some of the procedures in the QRH have the words “land at the nearest suitable airport” This means the crew needs to land as soon as possible and the safety of the flight is in jeopardy.

The QRH procedure for the engine failure scenario that I described above has that phrase in it. Some of these other mechanical problems also carry the “land nearest suitable” verbiage:

  • Cracked windscreen
  • A single source of electrical generator power
  • Any sort of fire
  • Pressurization failure
  • Engine fuel leak
  • Crew oxygen system low

The QRH procedure doesn’t always have to say land at the nearest airport to make the plane divert. There are many times where it would be safe and legal to continue to our destination but instead we decide to divert somewhere and have maintenance look at the aircraft before we continue; as in some of the situations I mentioned earlier. This happens a lot on our transoceanic flights. There are many times where there might be a mechanical problem with an airplane and we choose to stop along the coast before heading across the ocean- imagine a potable water issue that is not addressed before heading over the ocean (not good!). We know we can only get the plane fixed or change to a different aircraft before heading over the ocean. Being careful ensures the safety of all involved and also makes sure the return flight does not cancel.

As you can see there are many things that can cause a flight to divert due to mechanical reasons, they all might not be as severe as an engine failure but when we feel that the safety of the flight is in danger it is always better to put the aircraft on the ground somewhere.

Tomorrow in part three I will cover passenger related diversions.

777 photo from Airliners.net photographer somtam

Diversions, Weather Diversions (Part 1 of 3)

This is the first in a three-part post about diversions, while diversions are uncommon, they do happen, in my opinion, on average once out of 3000 flight at my airline.   There are generally three main causes for diversions: weather, which I will be the topic of today’s post, mechanical problems, and passenger issues. Each post will start out with a scenario that describes the type of diversion; these scenarios are from my past experiences. I hope you enjoy.

Imagine this. You’re on an airplane and you are approaching your arrival city of Chicago, it’s nighttime, you see that there are some thunderstorms off in the distance. You see the lightning coming out of the clouds and they are getting closer. Just as you notice this, the captain comes on the intercom and says, “Ladies and gentlemen, from the flight deck. I’m sorry to inform you that we are to be entering into holding do to some whether at the airport. There are thunderstorms at the airport and the no one is able to land at this time. We will try our best to sit and wait out the weather but it looks like it might be a while.  We will keep you updated from the flight deck until then please remain in your seats because it could get turbulent as we approach the weather. I have also asked the flight attendants to be seated for their safety.”

You are glued to your window and you are watching the lighting outside and feeling the jolts of turbulence as you gradually feel the airplane doing circles in the sky. After about 45 minutes of holding the captain once again comes on the intercom and says; “Well ladies and gentlemen the airport is still not opened and unfortunately we have ran out of holding fuel. We still have plenty of fuel on the airplane but we are going to have to divert to another airport. Instead of landing in Chicago will be diverting to Indianapolis. Our hope is to get some more fuel and get on our way back to Chicago once the weather clears. Again thank you for flying at Acme airlines and we will do our best to get you home tonight!”

If you are a leisure traveler the chances are you’ve never had this happen to you before. If you are a business traveler, or someone who flies quite frequently, chances are you have heard of, or have experienced this exact same scenario. If airlines could control the weather we would; and remember no one ever wants to divert including the airline.

Weather diversions:

Weather is the number one cause for diversions. Between thunderstorms, winter storms and fog; they all prevent the pilot’s ability to land the aircraft at an airport. Lets break these weather events down further. We will start with thunderstorms.

If there’s a thunderstorm over the airport you can’t land the airplane-it’s just not safe. There have been many crashes throughout the mid-70s and 80s that were attributed to microbursts, which are byproducts of some thunderstorms. Thunderstorms also reduce the visibility and create strong winds and even wind shear.  If there is wind shear present while an aircraft if trying to land the flight could loose the airspeed that is keeping the airplane landing.  There are instruments on board the aircraft called EGPWS that will give the pilots warning when they might encounter this wind shear.  This video explains the EGPWS system.

Winter storms, like a snow or ice storm, have two things that affect the ability of the pilots to land. The first thing is the visibility, which I will discuses with fog. The second obstacle to landing is the runway conditions. As most of us know, snow and ice create slippery roads, which means it also creates slippery runways. As you can imagine it is very difficult to stop an aircraft on a slippery runway. Quite often during a snowstorm the airport authority needs to close the runways so they can clear them and treat them. If there is more than one runway at the airport they will usually alternate them. This means only one or two runways will be open which reduces the amount of airplanes that can takeoff and land. When the airport authority closes a runway it is usually closed for about 15 to 20 minutes while the machines get on and clear the runway. If you have never been on a runway before think if it is clearing a 4-5-lane highway that is 1-2 miles (1600-3200m) long and you have to clear it from edge to edge. If able airport authorities will plan the runway closures for times where the arrivals and departures are low. The video below shows a runway team in action.

Another weather phenomenon that could cause diversions is fog. During heavy thick fog when the visibility is really low airplanes just can’t land. Every instrument approach has a set of landing limits or landing minimums. The crew cannot attempt an approach if the weather is below the published minimums. Due to today’s modern technology, diverting due to fog is becoming less and less common. Most modern airliners have the ability to land with just 600-foot (75M) visibility. In most cases, these CAT III landings are being flown by three autopilots on the aircraft with the pilots just monitoring to make sure the aircraft is doing what the pilots tell it to do (to my pilot readers, I know it’s a lot more difficult than that, and I admire your skill). Some of the regional jet airplanes do not have the ability to fly these lower landing min approaches. If the visibility is too low then these airplanes will not be able to attempt an approach. In many cases when an airport goes below CAT I landing minimums ATC will issue a ground stop for CAT I only aircraft.

Landing Minimums section of an approach plate

Landing Minimums section of an approach plate

The final weather phenomenon that could cause weather diversions is wind.  Strong winds coming from specific directions could cause strong crosswinds. All aircraft have crosswind limits, but it also depends on how the airline got certified and how they train their pilots. Most crosswind limitations range between 28 and 40 knots.  The rudder effectiveness determines crosswind limitation.  If the wind is too strong the rudder will not be able to straighten the aircraft to land and the airplane could land sideways.  A side loaded landing could cause damage to the landing gear or even cause the aircraft to crash.  In many cases crosswind landings are not a temporary condition. When there’s a strong crosswind the airport could be shut down for hours at a time.  To counteract this weather phenomenon, most airports have runways in multiple directions. However there are many major airports around the world that only have parallel runways.  When these airports get a strong wind perpendicular to their runway complex, there is no other option but to divert to another airport.  I know we have all seen the videos on YouTube of strong crosswind landings but there’s one below in case you have never seen a crosswind landing.  The airport is the old Hong Kong airport Kai Tak.  This airport closed in the late 90s but a large mountain at the end of the runway created a great vantage point for watching aircraft land.

I hope you enjoyed part one of this three part series about diversions. Tomorrow I will be talking about the next largest contributor of aircraft diversions; enroute mechanical failures.

Removing Dispatchers from the Cockpit Would be a Huge Mistake!

I am sure you have read by now that Southwest Airlines flight 4013 from Chicago Midway airport to Branson, MO landed at the wrong airport. As I said in my post Landing at the Wrong Airport is More Common Than You Might Think, this wasn’t the first time and it won’t be the last.  I am relived that the pilots were able to stop the aircraft on the short runway and there were no injures to the passengers or the crew.  I was surprised to hear that a dispatcher was reported to be in the jumpseat of the flight.  There has been some backlash from the media regarding people other than pilots to sit in the jumpseat.

I feel the greatest privilege and benefit that I have as a dispatcher is access to a flight’s jumpseat.  The reason a flight dispatcher is allowed to sit in the cockpit comes straight from the Federal Aviation Regulations.  FAR 121.463 states: “No certificate holder conducting domestic or flag operations may use any person, nor may any person serve, as an aircraft dispatcher for a particular airplane group unless that person has, with respect to an airplane of that group, satisfactorily completed the following: (2) Operating familiarization consisting of at least 5 hours observing operations under this part from the flight deck or, for airplanes without an observer seat on the flight deck, from a forward passenger seat with headset or speaker. This requirement may be reduced to a minimum of 21⁄2 hours by the substitution of one additional takeoff and landing for an hour of flight”  

A picture I took on my last required Jumeseat ride

A picture I took on my last required Jumeseat ride

This requirement for the flight dispatchers to observe the operations on the “routes they would normally dispatch” enhances the dispatcher’s knowledge of pilot procedures and allows dispatchers to see the procedures for flying in different types of airspace.  When I first became a dispatcher I did not know what it was like to fly a jet aircraft, I had only flown small prop aircraft.  Even though I had a commercial pilot certificate I was far from being certified to fly the aircraft that I was now dispatching.  The jumpseat requirement allowed me to understand the performance and complexity of flying a jet.

A few years ago I took my annual jumpseat ride to Mumbai, India.  I had been working the flight to Mumbai for about 6 months before I went on my jumpseat ride.  I really learned and understood the procedures that I needed to follow and provide the pilots for the high terrain over Turkey and the overflight procedures for flying over Iran. The only way for me to fully experience that route was to actually fly it from the jumpseat.  That jumpseat experience changed how I worked that flight.  After I returned from that trip I was able to provide more useful release remarks on my flight plans and I was able to accurately and confidently brief the pilots who had never been to BOM.

Photo from the Jumpseat on a personal trip.

Photo from the Jumpseat on a personal trip.

As you can see these jumpseat rides can be very useful and informative.  Not only can we sit in the jumpseat for our required trip but this requirement opens the jumpseat up to us for personal travel.  This personal travel is what allows me to get where I am going when the flights are full.  Sometimes I will choose to sit in the jumpseat to allow other standby passengers to get on the aircraft.  Every time I ride a jumpseat I see it as an opportunity to learn something new or to help the crew if needed.

While I do not know what happened on the Southwest flight that landed at the wrong airport, I do not think it will be prevented from happening again by banning jumpseat riders from the flight deck.

Related stories:

NTSB Issues Investigative Update on the Southwest Airlines Wrong Airport Landing Incident

Third person in Southwest plane cockpit may have distracted pilots

My experience with Fatigue and Ultra Long-Haul flying

Inside a Operations Control Center: The Brain of an Airline


FAR 117, the new pilot rest rules, started January 4th 2014.  As is predicted in my post FAR 117: The New Pilot Rest Rules Could Lead to Many Cancelations, these new crew duty rules have lead to cancelations.  This past week I have come to realize the true effect of FAR 117 on the airline industry.  Airlines will need to make changes to their operation to conform to these new rules.

These first few days with FAR 117 have been stressful; not only for the people in the operations centers but also to the crews and even the passengers.   As an airline, we are seeing a lot more “crew reroutes”.  This is when a crew gets pulled from the trip they bid and placed on someone else’s trip.  They still work the same amount of days but their hours might be less.  This new arrangement interferes with any personal plans the crew may already have had in place.  The passengers are affected because they’re seeing a lot more delays or cancellations.   The operations center has been a lot busier then normal the last few days.  People have been trying to learn these new rules in the middle to two major IROPS (irregular operations) and it seems like we have been scrambling to keep the operation together. These new problems are not specific to any one airline.  They are affecting the industry as a whole.

In a quick review, FAR 117 breaks the pilots duty into two types:  the pilots block time which is the point from pushback to taxi in and their duty day which is their total hours worked from check in to release.  Depending on the crew’s report time, their block time is limited to either eight or nine hours.  Their total duty day is dependent on their report time and how many legs they fly.

flight xld

This New Year has seen most of the Midwest and Northeast of the United States affected by winter storms.  The first winter storm happened right after the New Years and blanketed the Northeast with up to 20 inches (50.8 cm) of snow.  Today, a second winter storm is moving through the Midwest dumping a foot of snow (30 cm) and caused freezing rain in New York.  New York’s JFK airport was closed today for two hours as freezing rain made the runways and taxiways too slick for airlines to operate safely.

We ended up canceling flights between the Caribbean and the United States today.  The pilots were scheduled to fly from the United States to their destination in the Caribbean, then turn around and fly back to their origin airport.  Seeing as the crews took so long to deice out of the United States they ran out of block time.  This meant that the return flight had to be cancelled because they did not have enough block time left to fly back home.  In some cases the crews were just 10 minutes short on their block time limitation.  All of the canceled flights will operate tomorrow under a different flight number so the passengers will still get to where they want to go.  Domestically, as pilots get deeper into their duty day their block time becomes critical.  This means the afternoon shift faces the FAR 117 restrictions a lot more then the dayshift does.  I have not worked an afternoon shift since the new rest rules went into effect so I really don’t know how bad of a problem it is but I am told it is very busy.

While there’s going to be a learning curve at all of the airlines, I have notice some things that airlines can change to help mitigate the challenges of the new pilot rest rules.  The challenges start with crew scheduling and the people that build the pilots rotations.  At my airline, pilots have been given very little “wiggle room” on their block time and or duty day in their rotations.  In irregular operations like airlines have faced at the start of this year, “wiggle room” is needed.  Today if those flights to the Caribbean were two day trips instead of out and backs the pilots could have deiced, flown to the destination and laid over taking the return flight the next day.  While this looks like a great idea on paper airlines do not have enough pilots to allow this change.  Also, a pilot rotation like this would significantly increase the airlines costs.

The second problem that I noticed was a lack of training.  Many people do not know the difference between block time and duty time.  Most of the knowledge that I have on the new rest rules I have found on my own instead of from my company.   These new rest rules take into account both a crews block time and their duty day.  From what I have experienced it is usually only one of those two that limits that effects a crew.  As operations employees we really need to know how to identify a flight crews limitation and understand impact of those limitations before we make any decisions.  Airlines can not master their operation under these new rules until their decision makers fully grasp and understand the differences between block time and duty time.

One thing I am thankful for is increased visibility to the time that a crew has remaining to their day.  My airline has deployed some great automation to make everyone aware of each crews limits.  While the tools are great the knowledge to use those tools is lacking.  While my airline is only five days into these new rest rules I think that we can overcome the challenges they have brought.  It is going to take a few months before the airline industry fully perfects our operation under FAR 117 but I’m confident that we will get there.

In the meantime, I have a few suggestions for the flying public and airline employees:

For the flying public- Take morning flights, the morning flights will be less likely to have any FAR 117 issues and you will be able to make to your intended destination without any problems.  I also suggest that you have some patience.  Be kind to the airline employees that you encounter,  it is not their fault that your flight is delayed or canceled and if they could they would make sure your flight was on time.

For pilots and airline employees- bid early morning shifts with early report times.  If you can end your shift by 4 PM you should avoid most of the delays and cancelations.  For pilots, getting up very early limits your block time and your duty day because of the early start.  In doing that you are less likely to get rerouted because your scheduled flying gets you to your limitation faster.

This is going to be a chaotic few months but I think we will be able to look back on these few months and realize that these new rules really aren’t that bad and they do make aviation even safer.

It’s never a Good Thing to Have Jim Cantore on Your Flight

Today was my first day back to work since the New Year’s holiday. I was working a domestic desk that was working flights primarily to the Northeast; more specifically to Boston. Today there is a major winter storm that is moving out of the Midwest and across the Northeast. It is impacting Boston the hardest. When it is all said and done Boston is going to get between 15-20 in (38-50 cm) of snow. This was the first major winter storm that I’ve worked so far this season. There are many things that you have to consider when working a winter storm but the thing that worries me the most is the condition of the runway on landing. As you know, unlike rain, snow does not come off the runway on it’s own, it requires heavy equipment to remove the snow and to do so they have to close the runway about every hour depending on the intensity of the snowfall.

In winter events like this fuel is always your friend. On all of my flights to Boston I was carrying a good alternate and at least 45 to 60 minutes of holding fuel. This extra fuel onboard gives both the captain and I options when unexpected delays occur. I was making sure to update my crews on the conditions of the runways and what other aircraft were reporting as far as breaking. Pilots report braking action in terms of “good “, “fair “, “poor ” and “nil “. Today at Boston almost all of the breaking action reports were considered to be in the “fair” category. This means that the braking deceleration is noticeably reduced for the wheel braking, or directional control is noticeably reduced. Overall, I wasn’t too concerned about the conditions of the runways with all of the pilot reports calling it fair. When my flight was getting close to Boston they sent me a ACARS message telling me that they were entering a hold because runway 4R was closing so it could be cleared of snow. They also told me that runway 33L was now going to be used but first they wanted to hear what the braking action was before they attempted to land.

While the flight was holding north of Boston I decided to call up our scanner in the Boston area so I could listen to air-traffic control. Being able to actually listen to the air traffic control frequencies really helps aid and speed up the flow of information. I can hear real time what other aircraft are reporting and relay that information quickly to my flights that are inbound to the airport. I was watching all the Boston arrivals on my flight following monitor and I saw that another airline’s airplane that was the same type as my flight was going to be landing on runway 33L first. As I was listening for them to getting their landing clearance what the tower said triggered something in my memory, the air traffic control tower called the winds 050 16 gusting to 25 knots. When that other airlines aircraft called the braking action fair I knew that we could have a problem. My airline has a restriction that says we cannot land on a runway that has braking action less than good with more than a 20 knot crosswind. With the wind that the tower was reporting that runway had a 25 knot crosswind. I reminded the crew of that restriction because it is not often that we have to follow it and it is a restriction that is easily forgotten. The crew and I decided to try and hold until runway 4R opened.

Finally the crew called me on the radio. The captain I discussed the situation in Boston, the runway, the restrictions that we had and their fuel on board. The captain also mentioned they had encountered some moderate icing and had had to climb to get out of it. Aircraft icing happens when supercooled water droplets from the clouds hit the aircraft and freeze. The word moderate indicated that the ice was building up at a pretty heavy rate. We began to talk about where we should divert. I listed Hartford/Windsor Locks Airport as the flights alternate on the release, but just because that was the alternate that I chose during the planning process it does not mean that we had to actually divert there. After some consideration the crew told me that they thought that Providence would be a better alternate because it was closer and the weather was about the same. I looked at the field conditions in Providence and read the notams; I agreed that Providence could be used as an alternate and considering the icing, the aircraft’s fuel on board, the wind speed and direction, and the runway in use at Boston the captain and I decided to divert the aircraft to Providence to get more fuel.

Whenever your diverting an aircraft there’s a long list of people that you have to tell. First of all I had to call the station to let them know they were getting another flight. Then I needed to call the aircraft router to let them know that the flight was diverting so they could delay the aircraft’s next flights. Sometimes you might need to call maintenance so they can get mechanics to meet the flight. Once all that was finished I now needed to issue a flight release from our diversion alternate of Providence back to Boston. All of this takes place while you are still handling your other flights so your workload is increased. Whenever you divert a flight you always want to make sure you have enough gas on board for the return so you don’t end up diverting again. When he got on the ground the captain called me just let me know that they were on the ground safely and what was going on with the aircraft. That is when the captain told me that the icing on the aircraft was the worst he’s ever seen. He said there had to be over an inch of ice on the airplane. This meant the deicing out of Providence was going to take a while. After the crew told me that I asked them if they had taken any pictures (I have seen some iced up aircraft before and I am amazed how the ice builds up on the airplanes), they told me to watch “The Weather Channel” because, of all people, Jim Cantore had taken pictures!

In case you don’t know who Jim Cantore is, he is a famous meteorologist that works for The Weather Channel. In fact, as I’m writing this post I am watching him on TV hoping to catch a glimpse of some of the pictures that he might have taken of the airplane. Looking at his Twitter feed he did post this picture:

View of ice buildup on the ice detector.  Photo from @jimcantore

View of ice buildup on the ice detector. Photo from @jimcantore

His twitter feed also gave the passengers perspective on the diversion. There is a weather Channel commercial about Jim going on vacation to the beach during hurricane season, and everyone that sees him runs because they think a hurricane is coming. The video can be seen here. I have had him on my flight in the past, and the crew sent me an ACARS that said “Jim Cantore is on our flight, Anything we should know?”

While today was a stressful and busy day, I am glad that all of my flights landed safely and Mr. Cantore got to Boston so he could stand out on a snowy Boston street corner to report on today’s snowstorm.

Dancing the Medicine Bow Shuffle – Turbulence Avoidance was the Top of Yesterday’s Agenda

Dancing the Medicine Bow Shuffle – Turbulence Avoidance was the Top of Yesterday’s Agenda

While the Northeast United States was getting hammered with snow yesterday I, thankfully, was working flights to the Southwest United States. The weather was much better in the southwestern part of the United States with almost all the airports being VFR.  The only thing I needed to do on the flights I planned was avoid the turbulence.  Just because turbulence is common while flying, it does not mean that it is unavoidable. There are many things that dispatchers and pilots can do to avoid turbulence and give the passengers a smooth ride.  Most turbulence avoidance starts with the dispatcher during the flight planning process.  Dispatchers have the ability to plan the flight around the turbulence by either changing the altitude or the route the flight takes.

The turbulence that I was avoiding yesterday was a unique type of turbulence called mountain wave turbulence.  This type of turbulence occurs mostly in the wintertime when winds hit the side of a mountain range and get pushed upward.   The stable air that happens in the wintertime causes all of the air to be pushed up causing a wavelike action.  Below shows an illustration of what the waves look like, as you can see it’s called Mountain wave turbulence because it literally looks like waves on an ocean.  When a flight encounters a mountain wave, the airspeed decreases and increases and the altitude changes by a few hundred feet as the aircraft moves over the waves.  Mountain wave turbulence can be very predictable but also can be very severe.  The meteorology department at my airline has spent decades researching mountain waves in an attempt to better predict their occurrence and severity.  Their research is very specific to wind speed, direction and atmospheric stability of the air over specific mountains throughout the world.

As you can see the air hits the side of the mouton and because of the stability of the air a "wave" occurs

As you can see the air hits the side of the mouton and because of the stability of the air a “wave” occurs

The mountains over Alaska, Western Canada and the Western United States generally produce the most mountain waves.  On my flights yesterday the mountains that spread over Colorado, Wyoming and New Mexico were causing moderate mountain waves.  The meteorology department has broken the mountain wave areas into many different regions.  When they tag an area open, we have two ways to avoid these mountain wave areas: we can either fly completely around the area, or we can fly through the regions while following specific routes and avoiding the altitudes that the meteorologist defines.  Yesterday, I chose the first option; it was more economical to avoid the area completely than it was to descend and fly through the area.

I learned very quickly once I started working here the routes to use to avoid the mountain wave in this area.  The route uses the same two navaids; these VOR‘s are Medicine Bow (MBW) and Myton (MTU).  In our office we call this route the Medicine Bow Shuffle because it seems that we are shuffling all of our airplanes around the active areas. I took a screen shot of my graphical flight flowing display in the middle of my shift yesterday.  The magenta lines are the routes that my flights were taking and the small pink airplanes are my actual flights.  As you can see, most of my flight paths were intersecting at either MTU or MBW and than flying the route between those two VOR’s.  All of the airplanes are avoiding the orange polygons, which are the active mountain wave areas.  The other white dashed lines are other mountain wave areas that are not active.  While some of my flights still reported some mountain wave action there was no turbulence associated with that wave while they were on the shuffle.

Green shot of my flights today avoiding the Mountain wave areas over the fixes Myton and Medicine Bow

Screen shot of my flights yesterday avoiding the Mountain wave areas over the fixes Myton and Medicine Bow

While yesterday’s flight planning and turbulence avoidance was specifically because of mountain wave turbulence, the concept of avoiding turbulence also applies to all the other forms turbulence.  A few times a day our meteorology department produces upper air depictions that show us where light, moderate, or even severe turbulence might be.  It is my job as a dispatcher to analyze the risk of the turbulence and decide if I’m going to fly through it or avoid it.  My personal rule of thumb is I will avoid any turbulence that will last over an hour, or if the turbulence is forecasted to be moderate or greater. My goal is to give passengers the smoothest flight possible while also taking into account the economics of the airline.  When the turbulence is completely unavoidable I always want to make sure the crew is going to know when and where the turbulence will start and how long it will last.  I feel if the crew has that information they can mitigate most of the risks on the airplane by telling the flight attendants to take their seats and make sure the passengers have their seat belts fastened.  While the ride through the turbulence might not be the smoothest at least it will be safe and no one will get injured.

If you want to learn more about mountain waves the YouTube video below is by some meteorologists in Alaska and gives more specific scientific information.

FAR 117: The New Pilot Rest Rules Could Lead to Many Cancelations.

As a disclaimer I am in no way opposed to the new FAR 117 rules and I agree with them and their purpose of putting rested pilots at the controls of passenger aircraft.  The purpose of this post is to show the potential impact of the new FAR rules on the operation of an airline. Here is the full text of FAR 117.

January 4, 2014 is when the new FAA regulations that govern flight crew rest go in effect.  These new rules are the result of a number of aviation accidents; with crash of Colgan Air 3407 being the ultimate motivator for the changes in pilot rest rules.  The new rules take into effect both the pilots actual duty day (the time they report to the time they are released from duty) and there actual flying time (the time they push a gate to the time they pull back into the gate).  That is similar to the current rest rules the big change is the duty day and flying time is limited by the time of day the crew reports.  For example if a two man crew’s report time is between the hours of  8pm and 4:59 am the crew is limited to eight hours of flying but if they report between 5am and 8 pm their max flight time is nine hours.  The new regulation also takes into effect the number of legs the flight crew flies, the more flight legs in a day the shorter the crew duty time is.  The charts below give the information. Table A and Table B illustrate the example I stated above.  Table C is is for augmented flight crews: (tables taken from eCFR.gov)

Table A to Part 117_Maximum Flight Time Limits for Unaugmented Operations Table
                Time of report (acclimated)                  flight time
0000-0459.................................................             8
0500-1959.................................................             9
2000-2359.................................................             8
Table B to Part 117_Flight Duty Period: Unaugmented Operations
                                               Maximum flight duty period (hours) for lineholders based on
                                                                     number of flight segments
Scheduled time of start (acclimated time)    -------------------------------------------------------------
                                                   1        2        3        4        5        6        7+
0000-0359...................................        9        9        9        9        9        9        9
0400-0459...................................       10       10       10       10        9        9        9
0500-0559...................................       12       12       12       12     11.5       11     10.5
0600-0659...................................       13       13       12       12     11.5       11     10.5
0700-1159...................................       14       14       13       13     12.5       12     11.5
1200-1259...................................       13       13       13       13     12.5       12     11.5
1300-1659...................................       12       12       12       12     11.5       11     10.5
1700-2159...................................       12       12       11       11       10        9        9
2200-2259...................................       11       11       10       10        9        9        9
2300-2359...................................       10       10       10        9        9        9        9
Table C to Part 117_Flight Duty Period: Augmented Operations
                                             Maximum flight duty period (hours) based on rest facility and
                                                                      number of pilots

Scheduled time of start (acclimated time)        Class 1  rest         Class 2  rest         Class 3  rest
                                                  facility              facility              facility
                                            3 pilots   4 pilots   3 pilots   4 pilots   3 pilots   4 pilots
0000-0550................................         15         17         14       15.5         13       13.5
0600-0659................................         16       18.5         15       16.5         14       14.5
0700-1259................................         17         19       16.5         18         15       15.5
1300-1659................................         16       18.5         15       16.5         14       14.5
1700-2359................................         15         17         14       15.5         13       13.5

How these new regulations could cause cancelations:

At my airline we have a large operation that flies to Mexico, Central America and the Caribbean.  Almost all of these flights are between three and three and a half hours one way. The pilots on these flights are scheduled to fly to their destination, spend between 45 and 90 min in that city and than fly back home.  For the pilots its a great one day trip.  However, if you consider a scenario that can occur a few times each summer, this great one day trip could turn into a two day nightmare.

Lets look at a hypothetical: Flight 123 is scheduled from hub airport (HAP – not the real airport code) to Tegucigalpa (TGU).  The flight leaves HAP at 1030 and arrives in TGU at 1315 the pilots and the aircraft then spend 1hr and 15 in TGU before flying back to HAP.  The flight leaves TGU at 1434 and arrives back at HAP at 1900.  In total the crew is scheduled for 10 hours of duty time and 7 hours of flying time.  Under the new rules the pilots will be limited to 9 hours of flying time and seeing as they are flying two legs and they reported for duty between 0700 and 1159 they can be on duty for 14 hours.  On the perfect day this looks sufficient but what happens when the day is not perfect?

The heat and humidity of summer in the United States creates the right conditions for what are called super cell thunderstorms to develop.  When these thunderstorms pass over an airport it causes the airport to stop landings and aircraft have to enter holding patterns until the weather moves across the field.  If a flight does not have enough fuel to hold until the airport reopens than they will have to divert to a secondary airport.  In our flight 123 scenario: the flight to TGU was uneventful it took 3 hours and 40 minutes of block time but there is a line of weather that is forecasted to be moving through HAP when the return flight 124 from TGU to HAP is scheduled to arrive.  The crew notices that they are planned to fly on a route that is 45 minutes longer than the optimal route due to a severe line of thunderstorms.  The new route makes the flight time back to HAP 4 hours and 20 min.  As planned, the crew’s block time for the day is at 8 hours of flying time.  This leaves just one hour before the crew exceeds their block time limit.

route diffrences

Optimal route to HAP is on the top and the longer route to avoid weather is on the bottom

As the flight approaches HAP, the line of thunderstorms has just impacted the field and they are told to expect holding.  The crew has 1 hour of extra fuel on the aircraft when they enter the holding.  While they are in holding their dispatcher tells them that the airport might not be able to reopen until the flight is out of holding fuel.  50 minutes later they are within 10 minutes of having to divert, the weather is just starting to improve, but the airport is not expected to reopen for 20 minutes.

Planes holding waiting for the weather to clear.

Planes holding waiting for the weather to clear.

Finally, the crew has to make the decision to divert to their alternate airport; five hours after taking off from TGU.  In total they have flown for 8 hours and 40 minutes this day and it will take them 40 minuets to fly back to HAP.  That would put the crew at 9 hours and 20 minutes of flying for the day; which under the new rules is over the limit and they are not legal to fly.  Assuming there are no other pilots at the diversion airport, the flight will either have to cancel or be delayed so the pilots can have their required 10 hours rest.  This strands the passengers in a smaller city.  The airlines will not be required to provide hotels for these passengers because the diversion was caused by weather.

Like I said earlier this scenario occurs 3-5 times a summer and impacts up to 50 flights.  These new rules are going to add another factor that the flight dispatcher and pilots will have to consider while managing the operation.  Starting in January we are going to have to more strongly take into account the pilot’s duty day.  In the situation that I described above there are going to be two options:  we can plan to divert right away and protect the crews block time in order to recover the flight or we will have to put a large amount of extra fuel on the aircraft to almost guarantee the flight will make it into their destination.

Like all changes these new rules and regulations are going to take some getting used to.   Airlines are going to struggle during irregular operations but I think the airline that will train their employees the best and implement the best automation to bring visibility to the new rules will have no troubles with these new pilot rest rules.  Only time will tell how these rules will change the industry.  I have confidence good will come from them.

Map Images from Skyvector.com
Picture of holding from flightaware.com
Charts from ecfr.gov

Happy Thanksgiving- I am Thankful for you

Today is thanksgiving here in the United States.  This is a day where we get together with our family and our friends and reflect on everything that we have and our blessings in the last year.  While today is a national holiday, airlines are still operating.  I worked this morning and the weather was great and there were no problems with any of my flights it was a true blessing.

Today, I am thankful for everyone that reads my blog.  A short 5 months ago I started writing this blog to promote the dispatch profession and to give a “back room” view of the airline industry.  I am amazed how far my blog has come in such a short time.  I am very grateful to my friends, Captain Jeff Nielsen of the Airline Pilot Guy podcast and Max Flight of the Airplane Geeks podcast for having me on their podcasts to help promote my blog.

As I smell the turkey cooking in our oven, I want to wish you a very Happy Thanksgiving.



Inside a Operations Control Center: The Brain of an Airline

The office where I work is called the Operations Control Center, some airlines call it: System Operations Control, Global Operations center or Network Operations Center.  While the name is not the same at every airline the general function of the office is the same.  The purpose of these operations centers is to bring all of the workgroups that have a voice in the operation of the airline under the same roof to allow a better flow of communication.  I am going to list all of the workgroups that are present in my office and give a brief description of what they do.  I hope you get a better understanding of the complex operation of a global airline.

"The bridge" this is the main part of the office.  The major decisions get made here

“The bridge” this is the main part of the office. The major decisions get made here


The flight dispatch group is the largest group in our office.  As I have written about before, a flight dispatcher’s job is to prepare the flight plan for all of the airlines flights.  They do this by looking at all of the weather at both the origin and the destination as well as the weather at the higher altitudes.  If necessary they will plan a flight to avoid as much hazardous weather as possible.  A dispatcher’s job does not end when they send the flight plan.  They are in constant communication with the flight crew, updating them on any changes in the weather or any other hazards on the route. Dispatchers are monitoring the flight from the time that it departs the gate until it pulls into the gate at the destination city.  If the crew, while en route, has any abnormalities; whether passenger related or mechanical, they call their dispatcher on the radio for assistance.

Aircraft Routing:

This is the group of people who assign the aircraft to fly the current schedule that marketing has published.  They also route aircraft to specific cities for their scheduled routine maintenance.  For example if a 737 needs to overnight in Chicago on a specific day it is their job to make sure that the aircraft is where it should be.  They also evaluate aircraft swaps to make sure required maintenance checks do not get missed.

Crew Tracking:

A crew tracker is responsible for keeping track of the Pilots and Flight Attendants, especially in an irregular operation or a diversion.  For example if Flight 123 from ABC to XYZ is on a lengthy maintenance delay and the crew that is on that aircraft is scheduled to fly a flight from XYZ to DEF the crew tracker identifies that the crew will not make their second flight because of the maintenance delay and they will use a different crew to cover the XYZ/DEF flight.   They are constantly monitoring and covering crews to help keep the airline running on time.

Sector Managers:

The sector managers are a sub group within the dispatch group.  These dispatchers do not plan or flight follow any flights.  Instead, they are in charge of a specific fleet of aircraft.  They work with the aircraft routers and the crew trackers to ensure that their flights are running on time.  If they have a problem with one of the aircraft in their fleet they have a few options: delay, swap, or cancel.  For example if one of their aircraft get taken out of service with a mechanical problem the sector manager chooses to either delay the flight for the aircraft to be fixed, swap to a different aircraft or in some cases use a different type of aircraft.   Their last option is to cancel the flight.  While this seems simple there are many down line ramifications for canceling a flight, when you cancel a flight the aircraft and the crew do not get to their next flight.  The decision to delay, swap or cancel a flight lies solely with the sector manager, but they seek the opinion of the crew tracker and the aircraft router since their decision affects both of these other sub groups.


The meteorology group forecasts surface weather for the airlines major hubs across the world as well as turbulence and the upper air wind patterns.  Our meteorologists create upper air depictions for all of the areas where we fly our aircraft.  They also create SIGMET like alerts for our flights.  The meteorology department also does special forecasts when there are major weather systems, like hurricanes and winter storms, which could impact our operations.  The sector managers use these forecasts to preemptively cancel flights out in front of the storm.  Many airlines have removed their internal meteorology departments and have contracted them out to a separate company.  I am thankful that I still have a meteorology department in my office.

Airport Customer Service:

Airport customer service is the group that advocates for the passengers.  While the office as a whole is focused on customer service and safety, this group is especially concerned with what happens to the customer during delays or cancelations.  When we do need to cancel a flight this group identifies what needs to be done with the passengers and gives input to what flights should or should not be canceled.  This group also helps arrange tight connections.  For example if there is a large group of passengers that may misconnect to their flight ACS will look to see what the impact of holding the next flight would be.  This group also acts as a liaison between the OCC and the airport stations.

Charter Desk:

The charter desk is our liaison for our charter operations.  They are in contact with the stations or FBO’s (Fixed Base Operator) and the charter coordinators to ensure the charter is run efficiently.  This desk handles all aspects of the operational needs of a charter.

Crew Accommodations:

This department manages all of the hotels and transportation to and from the airport for the crews.  If there is a diversion or any other irregular operation where the crew exceeds their duty day they will also set up the hotels and transportation for those crewmembers.  They also make sure that the hotels meet all of the contract requirements for the flight crews.

Duty Pilot and In-flight Duty Manager:

These two individuals are a 24-hour resource for anyone in the office.  Both the duty pilot and in-flight manager represent their respective work groups in the OCC.  The duty pilot is the primary flight ops liaison in the office and, as I have mentioned in previous posts, they truly give the pilot’s perspective on situations.  The in-flight manager is our go to for any problems with flight attendants.  Both positions report to the leadership of In-flight and Flight Operations.

Load Control:

Load control is responsible for the weight and balance of all of the airlines flights.  They ensure the pilots have the correct gross weight for their aircraft as well as the correct trim settings.  The document that they send to the flight crews also has the weight limit for the different runways that are available as well as the V-speeds (the speeds the pilots use to determine when the aircraft is at a safe speed to takeoff).  Load control also produces the fuel-loading message to the station.  They also alert the dispatcher when a flight is over weight.


Radio provides air-to-ground communication between all flights and their dispatcher.  Radio also transcribes all of the radio conversations between a flight and it’s dispatcher.  Radio also sends non-operational information to flights at their request.

Corporate Security: 

The Corporate security desk is the operational security liaison for the whole airline.  They monitor security threats to the airline, its customers, aircraft, employees and facilities.  They lead the resolution of passenger security issues and they assist the stations to meet the regulatory security requirements.

Maintenance Coordination Center:

The MCC is the second largest group in the office.  They monitor and take corrective action with any company aircraft.  They are grouped by fleet and each fleet of aircraft have one to four experienced A&P mechanics that provide real time technical assistance to mechanics on the ground as well as pilots in the air.  They are also in charge of the routine maintenance of the aircraft and moving parts between different cities to fix aircraft.

Solution Center:

This is the office’s own 24/7-technology department.  The solution center provides support for all of the hardware and software that is used in the office.  If there is a computer problem they will be at your desk in a matter of minutes to help resolve the issue.  They can also replace an entire desktop in about 10 minutes time.  They make sure all of the employees in the OCC have operating tools to do their jobs in an efficient manner.

Navigation Database:

This group oversees all of the different airways and navigational aids around the world.  They update our flight planning system every 28 days with the new information.  They build routes for the different city pairs and review different NOTAMS for any changes to the database.  They also provide and obtain over flight permits and landing permits for different airports, especially airports where we do not routinely fly.

ATC Coordinators:

This group is also a sub group of dispatch.  Their major function is protecting the airlines interests when air traffic control places restrictions into some the nations busiest airports.  They also monitor and communicate to dispatcher about: ground stops, ground delay programs, and required and recommended re-routes.  This group also monitors the airlines regional partners to ensure they are giving the same quality of on time service as the mainline airline.

As you can see, there are many departments that are represented inside the operations center of an airline.  The decisions that get made in this office literally run the airline and directly affect its passengers.  This office is so important to the operation of an airline there is even a backup facility that is prepared to run operations to the same level of efficiency if the need ever arose.   It is the brain of the airline.

one "wing" of my office

one “wing” of my office

Information is the Best Motivator, Convincing a crew to continue with good information

Last week I was working a desk that sent flights to and from Central America.  Near the end of my shift I had a flight call me on the radio; the flight had been in the air about 40 minutes and they suddenly had a mechanical problem. It was an Airbus aircraft, and the crew told me that one of their flight management guidance computers (FMGC) had failed.  I patched the flight through with our maintenance department to help resolve the issue.

There are two manuals for mechanical problems that aid us in the decision making process, The Minimum Equipment List (MEL) and the Quick Reference Handbook (QRH).  The MEL is for maintenance problems that happen before the aircraft takes off.  This document tells us what can and can’t be inoperative on our aircraft and what procedures the pilots and dispatchers need to follow when a component is inoperative.  The QRH is the manual that the pilots use for maintenance problems that occur after takeoff.  This manual gives step-by-step guidance to help resolve the issue.  Usually when a flight calls with a maintenance problem they have already read the manuals to try and get the maintenance issue resolved; so I need to hurry and catch up in order to have the same information to reference.

On this flight the crew said, “the MEL says we cannot go into Class II airspace”  (Class II airspace is when you are no longer in range of a ground based navigational aid and the crew is using the equipment on the aircraft to navigate.) After acknowledging what the crew had said I told them the MEL did not apply because they were airborne and to standby while I read the manuals.  After reading both the QRH and the MEL (I read the MEL because the aircraft’s next flight was also one of my flights and I needed to see if we could operate the flight back), I saw where the crew said they could not fly into Class II airspace for the return flight but there were no restrictions in the QRH pertained to their current flight.

The crew seemed very hesitant about continuing the flight because they were very concerned about what was going to happen to the aircraft once it got to its destination.  I took a look at the crew’s rotation and understood their concern; they were on a one day out and back trip.  This means the crew started the day in their base and would fly to a destination and than fly home in the same day.   The crew suggested that they return to the origin airport because they “did not want to get the aircraft stuck at the destination.”  I figured they also did not want to get stuck at the destination.  If they returned to their base they would need to be replaced because they would be over their duty day.  I felt their thought process was valid. I was also concerned about having a broken aircraft in Central America.  Before I could just let the aircraft turn around and return to the origin airport, which I did not want to do because I felt is was safe to continue, I needed to consult with the aircraft router for her input.  I also needed to see if there was a way to get the aircraft back with the FMGC inoperative.

In this case there was a way to fly the aircraft back, I just needed to route the flight around the Gulf of Mexico back to the United States. When I gave the crew the plan to fly around the Gulf of Mexico they told me they might not be legal to fly that route because of its length, it was another thing for me to check on. While all of this was going on the flight was still troubleshooting with maintenance.  The maintenance controller had just given the crew instructions for a seven-minute reset on the flight computer.  I saw these seven minutes as the opportunity to gather information and develop a full plan.  In these seven minutes I needed to:

  1. Plan a route around the Class II airspace in the Gulf
  2. See if the crew had enough duty time to fly that route
  3. Seek the operational impact from the aircraft router if we returned
  4. See if the flight was going to be over max landing weight for the return flight if I fueled the aircraft for the longer route but the short route over the Gulf could be flown
  5. Develop a sales pitch to the captain
Route around Gulf if Mexico avoiding Class II airspace

Route around Gulf if Mexico avoiding Class II airspace

After the seven-minute reset was over the crew informed maintenance and myself that the computer was still not fixed, this was my moment to give the crew all of the information I had gathered and urge the captain to continue the flight to its destination.  I told them: “There are no other aircraft at the origin airport, if we return the flight will be canceled.  I feel it is as safe to continue to the destination, as it is to return following the guidance in the QRH. The route for the return flight around the Gulf avoiding the class II airspace is 57 minutes longer than the flight across the Gulf. Making the total block time for the return flight around 4 hours and 25 minutes.  If everything goes as planned on the current flight your total block time for the day will be 7 hours and 25 minutes (limit for a duty day is 8 hours). I am going to file your return flight avoiding Class II airspace, if the computer resets on the ground we will re-file on the normal route across the Gulf of Mexico. If this does happen you will still be under max landing weight back home. I have coordinated with ACS (airport customer service) about your connections on the return flight and they will do their best to hold those flights”.
  The crew had some clarifying questions about their duty day, which I was able to answer.  The only request was that I post an early departure for the return flight to give the connections a better chance of making their flights.

Route across the Gulf through Class II airspace

Route across the Gulf through Class II airspace

My shift ended just as the flight was landing; even though I did the release for the return flight it was now the responsibility of the next dispatcher. I fully briefed my relief of the situation and the plan that was laid out already. Later that evening I looked and the flight was able to fly over the gulf on the return flight. I was very happy that the aircraft got fixed and the crew and the passengers made it back on time.

[Pictures form SkyVector.com]