Plane Answers: Sunburns and inflight icing

Welcome to Gadling’s feature, Plane Answers, where our resident airline pilot, Kent Wien, answers your questions about everything from takeoff to touchdown and beyond. Have a question of your own? Ask away!

David asks:

Do pilots get sunburn from being up at 39,000 feet for several hours? Especially during the transcontinental day trips. If so, how do you protect yourselves?

I’ve never had an issue with sunburn while in the cockpit and apparently that’s because windscreens on airliners block the UV-B light which causes sunburn.

More worrisome is the fact that airline crews are classified as radiation workers in Europe and the United States. In fact, the level of radiation that crews are subjected to is in the top 5% of all radiation workers, and occasionally twice as high as a typical nuclear plant worker.

This radiation has caused an increase in cataracts among pilots as well as DNA damage among the more high time aviators. And if that weren’t enough, the incidence of melanoma is also slightly higher among air crew.

Dan brings up a timely topic:

After taking off in winter conditions with everything done properly for the de-icing of the plane is there anyway that snow or ice can accumulate on a plane while in flight? If yes how would this happen?

Inflight, we use engine anti-ice, which is essentially hot bleed-air from the engines piped through the leading edges of the engine cowl and, on some airplanes, the nose cone or ‘spinner’ of the jet engine. This anti-ice feature is left on anytime we’re in the clouds and the temperature is below 10C/50F.

This same hot air is piped through the leading edges of the wings. As ice begins to build up, we turn on the wing anti-ice to eliminate the ice. Unlike the engine anti-ice, wing anti-ice isn’t left on, however, but it’s cycled in intervals.

The tops of the wings remain free from ice inflight for the most part.

Also, the windshield is electrically heated whenever the engines are turning on a jet. This prevents frost and fog from building up on the outside and inside, respectively.


We need your help! Do you have a question about something related to the pointy end of an airplane? Ask Kent and he’ll use it for next Monday’s Plane Answers.

Cockpit Chronicles: Anatomy of a 26 hour delay.

You’ve booked your honeymoon cruise and since you’re smarter than the average traveler, you planned to be in San Juan more than a day early just to be safe.

Sometimes though, no matter how hard we try, forces just stack up against passengers and their flight crews. The San Juan one-day trip I flew just before Christmas is the perfect example.

Two 757s diverted into New York the night before because of a snow storm, and one of them happened to be our airplane for the noon departure from Boston to San Juan. I’d been called out to cover a trip on reserve the night before, so I watched with interest the progress of our airplane in the morning.

To make matters worse, another 8 inches of snow had fallen overnight at my house, so I had to snow blow the driveway at 7:30 a.m. for an hour. I wasn’t too surprised when the company called to tell me we’d be delayed until 1:30 p.m. while the airplane was brought up from New York.

I finished the driveway and checked the computer. Our airplane was being ferried (flown empty for repositioning purposes) from JFK by another reserve crew.

I made it to the airport for the later departure, but my captain had signed in earlier in the morning, before we knew the flight would be delayed. That meant his clock had started to run, counting toward the 14 hours of maximum duty day he was allowed to fly. Surely this wouldn’t be a problem, right?

Our airplane finally arrived an hour later than planned after sitting on the taxiway in New York in heavy snow. The flight had a taxi time of over an hour while it snowed at Kennedy.
Unfortunately, the pilots discovered a high stage bleed-air valve light had illuminated during the ferry flight, which meant that maintenance would have to try to fix the problem before we could depart, if they had the part in stock.

Bleed-air is the air that’s pulled from the engines to pressurize the airplane and heat or cool the cabin. There are two valves, a low stage and a high stage, that open depending on the amount of air needed. When the High Stage light is illuminated, it means that the valve is not in the position that’s being demanded at that moment. In our case, it was probably stuck open.

This was going to be a big job. And the task was made especially tough, since the other airplane ferried up from New York to be used for a Providenciales flight had a mechanical problem serious enough that it may be necessary to cancel that flight. I never did find out what the issue was on that airplane.

Not only that, but the 767 immediately to our right had an issue where both engines weren’t accelerating at the same rate–a problem that would take at least an hour to fix.

Maintenance was determined to get at least one of the three flights out of town that snowy, cold afternoon.

It was decided that the priority would be placed on the transcon 767 flight and our flight. Apparently the Providenciales flight had bigger problems than we did.

The mechanics estimated it would take two hours to change the bleed valve, since they had a replacement part available. They went to work right away in the blowing snow, opening the cowling of our right engine and crawling to the top of the compressor section while the 30 mph wind made the 12 degree air feel like -10 degrees F.

These mechanics were the real heroes that night. They never complained for a moment, even though the two hour job turned into a seven hour project. We stayed with the airplane and occasionally wandered into the gate area to answer questions.

Passengers were understandably frustrated and worried about their connections to various cruise lines. I couldn’t help but empathize with their situation. I tried to give them as much detail as possible, so they at least had an idea what was happening.

I usually leave this kind of discussion up to the captain, but when he wasn’t around, I braved the annoyed crowd to give them updates. To get more information, I checked on the mechanics, but I really didn’t want to pester them too often.

I never saw these guys take a break, and finally, after spending six hours in the cold, they had changed the valve.

By this time, we were within an hour and fifteen minutes of running out of duty time. We needed to be able to complete the 4 hour flight from Boston to San Juan within the 14 hour maximum duty day. And even though the valve had been replaced, the engine still needed to be started at the gate, shut down and then opened up again to check for any leaks.

If it passed the leak check, the next step was to taxi with the mechanics to a safe place to perform a high powered run-up. It was going to be close, but if we could get the passengers on the plane and the door closed before our 10:15 p.m. deadline we could make it.

I went to the gate to explain the situation to the waiting passengers while maintenance closed up the cowling and ran the engine. I was impressed that, while most of the passengers were frustrated with the situation, they genuinely understood what we were up against and that we were all trying to make it work.

Finally at 9:45 p.m. we had the engine running. It took far longer than expected just to get the cowl closed, probably caused by the cold weather. And after the idle run at the gate, the HIGH STAGE light illuminated again.

The mechanics were understandably upset that their 6 hour effort was for nothing. Since we were now out of duty time, they would have to take the airplane out of service and they could look at what else could be causing the problem.

I dreaded walking back to the gate area to explain our situation to some of the passengers, a few of whom I’d actually got to know as the hours passed. I know I’d be furious if I were them. Waiting 11 hours only to find out they’d have to try it again the next day had to be torturous.

Passengers were given hotel and meal vouchers and were told to come back tomorrow morning for a 9:30 a.m. departure. We figured a new crew would be called out to cover that trip, but surprisingly we were put up in a Boston hotel so that we could be given the minimum ten hours of rest before coming out the next morning to take our frustrated passengers in a different airplane to San Juan.

I went to a computer at another gate to find out what was happening to our schedule. Coincidently, the 767 that had been fixed next to our gate also ran into crew legality problems, causing another cancellation. So we fielded questions from a few of their passengers who were just receiving their hotel vouchers.

The captain and I jumped in the hotel van with a couple who had left Chicago that morning in a snow storm, before arriving in Boston to continue with us to San Juan. The new bride was nearly in tears at the thought of missing their cruise. But if everything went smoothly, we could still ge
t them there the next day before the 8 p.m. departure of their ship.

Naturally, the next morning a nor’easter hit the New England area and we’d need to be de-iced. After arriving at the gate, we discovered that our flight had rescheduled for a departure an hour and a half later at 11 a.m.

I thought of the newlyweds as well as others with 4 p.m. cruise ship check-ins. These passengers did everything right. They planned their arrival the day before the ship left, allowing for plenty of time in case of a delay in their flight. And yet they still might not make it.

We waited just over an hour for an airplane next to us to fully de-ice. The runway was opening and closing as plows were trying to keep up with the heavy snowfall. We needed to be de-iced with a two step de-ice/anti-ice process that would take 40 minutes to complete.

Twenty-five hours after we were originally supposed to depart, the de-ice crew came on the radio.

“Captain, prepare your aircraft for de-icing,” said the de-icer.

I turned off the air conditioning and engine bleed air, which prevents the sweet maple-syrup smelling de-ice fluid from entering the cabin.

There was nothing left to do but wait for the two trucks to de-ice our wings and tail. I spent the time snapping pictures to share with you, of course.


An hour later, we called for clearance to taxi.

“Did you pick up your clearance?” the ground controller asked.

“Yeah, we got it via PDC (the ACARS box).” I said.

“Well, we don’t have anything on you. You’ll need to re-file it.” The controller responded.

Oh, no. Our IFR clearance with ATC was good for a two hour period. We exceeded that by just a few minutes, which would require our dispatch to re-enter our flight plan information and send it to the FAA controllers.

I looked up the frequency to contact our dispatch while kicking myself for not thinking of this earlier.

Thankfully, after less than 3 minutes, our dispatcher had the new flight plan in the system. The controller could then let us taxi.

If our taxi time exceeded between 40 minutes to 1 hour and 20 minutes, depending on the snowfall intensity, we’d need to be de-iced again. Fortunately, the taxi was very short with only one airplane ahead of us. We were finally on our way.

We were scheduled to arrive in San Juan 30 minutes past the time our return deadhead flight was to depart. But there was still a chance that the deadhead flight would be late, since it had also come out of Boston that morning before flying to St. Thomas and then San Juan.

We just might make it, I thought. Once we were within 200 miles of San Juan, I called our company on the radio. I was dying to know if we’d be going home that day or if we had to stay the night in San Juan. The one-day trip had already turned into two, and I really didn’t want it to become a three-day trip.

“The flight to Boston has just arrived. You should be able to make it,” said our operations agent on the island. What a relief. Things were looking up.

Moments later, the agent called back. “It looks like you’ll all make it on the flight back to Boston tonight, but the co-pilot has been reassigned to fly to Miami.”

This job has its moments, and at some point, when things get turned so far upside down, and schedules are thrown out the window, you just have to laugh–it’s the only thing left to do.

I keyed the mic and said, “Ahh, you’re breaking up. Can’t hear you at all.”

We landed in San Juan at 6 p.m. I’m not sure if that was enough time for the newlyweds to make their 8 p.m. cruise, or how the other passengers did, but I sure hope it worked out for some of them. A first class passenger gave me an employee recognition card, which, under the circumstances was a nice thing for him to do.

A few hours later, I met up with another captain, a check airman who had also been reassigned to fly this trip from San Juan to Miami. Apparently the flight from Hartford had also left late enough that the cockpit crew couldn’t continue, so they used us to work the Miami flight. The captain I was flying with was from Sweden, and he kept me entertained with some great stories all the way to Florida.

I stayed the night in Miami before getting on the first flight back to Boston the next morning. Fortunately, they had a first class seat available.

After a few minutes had passed from our departure time, the captain got on the PA and said, “Ladies and gentleman, we have a problem with our hydraulic system that’s going to require a part brought over from the hangar. Since we’re not going to have air conditioning, we’d like to ask you to get off the airplane until we can get this problem resolved.”

I just smiled. I was sure it was payback for the past twelve months worth of mostly smooth flights with minimal delays and very reliable airplanes.

Luckily, just two hours later, we were on our way home to Boston. All I had to do was enjoy the view from the passenger window…

Cockpit Chronicles takes you along on some of Kent’s trips as an international co-pilot on the Boeing 757 and 767 based in Boston. Have any questions for Kent? Check out Plane Answers.

Plane Answers: Frost on the wings and non-flying pilot duties

Welcome to Gadling’s feature, Plane Answers, where our resident airline pilot, Kent Wien, answers your questions about everything from takeoff to touchdown and beyond. Have a question of your own? Ask away!

Paul asks:

Can a plane take off with frost on it or does it have to be de-iced ?

In the U.S., the FAA’s Federal Aviation Regulation 121.629 (c) says:

(b) No person may take off an aircraft when frost, ice, or snow is
adhering to the wings, control surfaces, propellers, engine inlets, or
other critical surfaces of the aircraft. Takeoffs with frost
under the wing in the area of the fuel tanks may be authorized by the

While there may be cases where some frost is allowed on the fuselage or even the bottom side of a wing, any frost, snow or ice on the wings and tail must be de-iced before takeoff.

De-icing technology has advanced significantly in the past 20 years with the increased use of newer anti-ice fluids. Previously we would de-ice with what’s called ‘type-1’ fluid, which removed the ice and snow from an airplane, but didn’t protect the wing from any further snow accumulation.

After de-icing, we have what’s called a holdover time. If we weren’t off the ground within the time specified in the holdover charts, we would have to have the wing inspected to ensure that snow isn’t accumulating or we’d have to be de-iced again. It wasn’t uncommon for a flight to make a couple of unsuccessful attempts at taxiing for takeoff within the holdover time.

Today we use a two-step process when it’s snowing outside. We still de-ice with type-1 fluid, either at the gate or after we push back and then our de-ice crew will apply a type-IV fluid, which has anti-ice properties.

You may have seen a wing with the thick green fluid on top. As snow continues to fall, this fluid can prevent any accumulation on the wing for well over an hour, depending on the conditions. This is a huge improvement to the type-1 holdover times which were as short as 10 minutes.

Unfortunately this two-part process takes at least 30 minutes to complete, depending on the amount of snow on the wings. I’ve had it take well over an hour, in fact. And that doesn’t include waiting for the other airplanes to finish before the de-ice crew can start on our aircraft.

Airlines are incredibly conservative about de-icing. Because of some high profile accidents that occurred in the early ’80s, we understandably still get many concerned questions from nervous passengers about the process.


Tom asks:

Hey Kent,

In a lot of your Paris trip posts you mention “non-flying duties.” What are these non-flying duties? How long do some of these take and do you have any paperwork to fill out after a flight like a police officer does at the end of his day? Or do you just fly and land and once your trip is done go home?

I may have been talking about non-flying duties as they relate to a pilot who’s not the flying pilot on a particular flight. Since the captain and co-pilot swap ‘legs’ allowing one pilot to fly the trip over and the other to fly back, the pilot not flying handles most of the non-flying duties.

This mainly involves communicating with ATC, but it also includes bringing the landing gear and flaps up and down and a few specific tasks such as setting the target altitude and headings when the other pilot is hand-flying.

The non-flying pilot usually pulls up weather and types any messages to the company via the ACARS unit as well.

After we arrive at our home base, it’s just a matter of saying goodbye to the passengers and the rest of the crew, jumping on the employee bus and driving home.

One of the best parts of the job is the lack of homework, with one exception; we change out hundreds of pages in our Jeppesen approach plates and aircraft operating manuals between trips. These packaged updates take about twenty minutes each, and we tend to get four to eight a month.

I personally have the added non-flying duty of writing about some of the more interesting trips, and sharing photos and video with you, although I’ve been running a few weeks behind in these Cockpit Chronicles posts.

Do you have a question about something related to the pointy end of an airplane? Ask Kent and maybe he’ll use it for next Monday’s Plane Answers

Cockpit Chronicles: How pilots choose their schedules

Today’s flight was a turn (out and back in the same day) from Boston to Santo Domingo, in the Dominican Republic. The airplane was a 767, which is always nice to fly. We’re able to fly either the 757 or the 767 using the same procedures and training. I think most pilots prefer flying the 767 versus the 757. It’s something we don’t see as often and it handles differently — a little like going from a Honda’s power steering (the 757) to a Cadillac (the 767).

We had some snow pass through Boston a few hours before departure but the airplane was already de-iced and ready to go by the time we arrived. Since the flight time was over 8 hours for the day, we had a relief co-pilot (FB) on board. Tom was the FB, which meant he would typically do the walk around inspection while I did the interior preflight. I stayed nice and warm while loading the FMS (flight computer that stored our flight plan and works similar to a GPS) and checking the equipment.

The flight down to Santo Domingo went without a hitch. We talked a bit about what trips everyone would be flying in March. For most pilots, there are two dates around the middle of the month that are almost like Christmas. The first is the day our bid sheets come out and the second is the day we get our schedule for the next month. A bid sheet is a print out of every possible schedule we can fly. It shows the trips and the days you’ll be flying them. You simply arrange your preferences in the order you want to fly them and hope someone more senior doesn’t pick the schedule that you’re hoping for.

For those pilots flying the 757 and the 767 internationally from Boston, there are 27 different schedules we can choose that fly four different kinds of trips:

  • Turns (one-day trips) – to Saint Thomas, Santo Domingo or Aruba. These high time trips give you the most days off.
  • A three-day Barbados – not much flight time, which means you’ll fly more days in a month, but the full day on the beach on the second day makes up for that.
  • The two-day London – a high time trip that most pilots prefer.
  • The three-day Panama City and Caracas – that departs very early the first day and gets back after midnight on the third day.

These trips change every couple of months, which is why the bid sheet is eagerly awaited every month. Even though there aren’t many different destinations to choose from, I can’t remember a time when we’ve had so many quality trips. I’d be thrilled to hold any of the first three trips above. The Panama City and Caracas layovers tend to go junior, meaning the pilots with the least amount of seniority usually fly there. Even after 15 years at the company, I’m relatively ‘junior’ on the list, with 4/5ths of the other co-pilots above me. The first six pilots usually choose the London flights, and the Caribbean turns where you’re home every night are usually the next most popular.

If you’re at the bottom 20%, you’re likely to find yourself on reserve, which is like being ‘on call.’ If someone calls in sick, the company will call you to fly. Usually you find out what you’ll be doing the day before. Reserve pilots usually fly less often than a scheduled pilot would and they get paid a flat 90% of a full schedule.

I’ve been lucky enough to hold a line for the last six months straight, but I was awarded a reserve schedule for next month. Hopefully I’ll get called out for a NY or Miami based trip (they often run short of pilots there) to someplace we don’t fly to from Boston.

We go to training every nine months, and I’m scheduled to go down for five days of training next month. Of course I’ll be writing about that.

As we approached Santo Domingo today, we had our usual challenge in understanding the controllers there. The tower controller was especially difficult to understand. Since the runway is closed for repairs, we’re landing on what was formerly the taxiway. Because of this, we had to turn around on the runway to taxi back to the gate. After our runway “U-turn” we were looking straight at a Cessna Caravan a few hundred feet off the ground heading toward us. The Caravan pilot obviously saw us, and I’m sure he just continued his approach until it became completely obvious that the controller’s plan wasn’t going to work. He went around and lined up again for landing a few minutes later.

Maybe I’ll bid around flying to Santo Domingo for a while. With just a little more seniority I should be able to reliably hold the Panama City/Caracas trips. And once you get a schedule, you are free to trade around, which is how I’ve been able to fly to London and Barbados on occasion.

With your seniority number deciding what trips you fly, what base you fly from, when your vacation occurs and, most importantly, when you will upgrade to captain, you can imagine just how important this number is to pilots. It’s so important, in fact, that it can even hold up an airline’s merger plans.

Cockpit Chronicles takes you along on each of Kent’s trips as a co-pilot on the Boeing 757 and 767 out of Boston.