Wing Contamination

[loopa]

Hi, to all you experienced guys, at what point do you guys consider it okay to take of with clearly visible contaminated wings?

Example, was on a flight last night and had a seat sitting by the wing. The wing looked more contaminated than an ice rink after a period of hockey. It could have easily been "stuff that could have flown off" or "stuff that could have stuck to the wings." Something that I think needed more inspection, and that a simple look wouldn't qualify as safe. Hopefully I'm wrong and can learn something from this...

We push back, taxi away, and as I see the de ice trucks just move from one corner of my eye to the other, the strobe lights go off and thrust is set.

We took off normally and the flight was uneventful.

So at what point is taking off with a contaminated wing considered okay (aside from AFM/POH values)? Because surely, by the time the pilot's checked the wings (before boarding), and by the time I was on the airplane, was at least 45 minutes (due to delays), no body checked the top surface condition of wings - and conditions were wet at -10. I was sitting at the row with the "triangle" indicated on it, specifying that it's the place to check for wing condition.

Thanks for the insight!

[Beefitarian]

If the wing is covered in fluffy snow even though it looks bad it will blow off before your airspeed is high enough for take off, so it's not going to be a problem. The issue here is if that fluffy layer is covering something that's attatched to the wing that could be a problem. It would be the pilot's responsibility to check for contamination and decide if he needs a de-ice or not.

[Hawkerflyer]

For me, I require a clean wing for ops. Like beefitarain said, what's under the fluff??

Here's a "did you know"

When The DeHavilland Aircraft Company first certified their 125 (later know as the Hawker 600) the airplane was approved for takeoffs with up to 1" of ice on the wings! Later, when they were bought out by Hawker Siddley, this was changed to a mandatory clean wing for ops.

I'm sure the crew was well aware of the situation.

[FICU]

Which airline?

I was sitting on a flight out of YYC with one Canada's larger airlines after the plane sat out overnight under clear sky's and I don't think the pilots even looked at the wings. There was solid frost covering the entire rear portion from the fuselage to the winglets including flaps, spoilers, ailerons, and the area of the wing in front of the ailerons although there was no frost on the top of the wing over the fuel tanks. After we pushed back and started engines with no announcement from the front about deicing, I brought it to the attention of an F/A who then passed it on to the flight deck. We stopped the push and the Captain made a bullshit announcement that it was just fuel frost on top of the wing(he obviously had not even looked at the wings) and that he'd have the F/O come out and inspect it. The F/O came out and didn't even walk back far enough to to see the frost on the rear of the wing as he was looking for fuel frost. The F/A came back to my position(on the trailing edge) and looked again and then after a few minutes the Captain said there would be a tactile inspection made. The rampy put a ladder by the leading edge of the wing and checked on top of the slats, which of course were clean. Surprisingly, no one but the F/A cared to look at the rear of the wing, which is were I had reported the frost.

After the first deice truck broke and the second one made it to us we were quite late and the Captain in all subsequent announcements sounded quite agitated. His first announcement of the morning was about how we were going to be early for our arrival at destination.

This is the second time I have experienced this on this airline, the first time another pax brought it up to the F/A and we then deiced. At this level the crews should know that frost forms more easily on the thinner parts of the wing(flaps, spoilers, and ailerons) and that it should always be inspected.

I can't believe I'm saying this but I'm seriously beginning to wonder if this is a cost cutting measure and or a way to keep up a good OTP record. I sure as hell hope not!

[J31]

I can't believe I'm saying this but I'm seriously beginning to wonder if this is a cost cutting measure and or a way to keep up a good OTP record. I sure as hell hope not!

I am sure it is not a cost cutting procedure. However as like a lot of things in life mistakes can be made, judgements exercised, things missed, etc….!?

Operating an aircraft requires a lot of teamwork and everyone, including passengers have a vested interest in a safe, uneventful flight to the destination. If you are sitting in the back and see something you do not like then speak up making your concerns known. If you are not happy with the solution, disembark.

However there are still lots of pilots that are allergic to de-icing and need to be nudged into it.

[SAR_YQQ]

Good posts by all - I'm glad we haven't seen any reckless comments so far.

How much contamination is acceptable? None.

[xsbank]

Take a look at this: http://www.batraining.com/eLearning/Fre ... reness.asp

If you fly contaminated you don't GARA about safety. But if you go against the AFM or Limitations you are probably flying without insurance - maybe your wallet might persuade you to clean the a/c? Good luck to you if you prang.

[RatherBeFlying]

I remember paxing from YYC in the Summer on a WardAir A310. There was frost on the upper wing surface over the wing tanks. The rest of the wing was clear; so, I kept quiet and sent a inquiry up through channels when I got back. The CP replied that A-310 manual allowed takeoffs with frost over the wing tanks.

Subsequent to the Dryden report, the CARs were changed to require squeaky clean surfaces.

Aerodynamically it depends, on the surface area, location and aircraft type. Types without slats (eg. Fokker, RJs) tend to be considerably more sensitive to frost.

Unless you intimately know how wing contamination testing was performed during certification, it's best to be chicken and report any and all upper surface frost. Nasty looks are not nearly as bad as going off the end of the runway at zero feet and 150 kt.

On the other hand I've seen deicing applied on a cold clear day when I could not see any frost at all.

[Go Guns]

The CP replied that A-310 manual allowed takeoffs with frost over the wing tanks.

Subsequent to the Dryden report, the CARs were changed to require squeaky clean surfaces.

Certain aircraft are still allowed to takeoff with frost on the wings caused by cold soaked fuel.

[pika]

Operating an aircraft requires a lot of teamwork and everyone, including passengers have a vested interest in a safe, uneventful flight to the destination.

All true, however, passengers are not required to attend annual cold weather/de-icing training to ride the airplane so those that are required to attend the training should be making the right decisions.

[FICU]

Certain aircraft are still allowed to takeoff with frost on the wings caused by cold soaked fuel.

I believe Westjet has an exemption for cold soaked fuel frost within the black box painted on top of the wing.

I think too many pilots think that the light fluffy snow on the wing will blow off but if you have been at altitude long enough after landing the cold soaked frost will form and the snow will stick to it so make sure the tactile inspection is over the fuel tanks and not just wiping the snow off the leading edge.

[ajet32]

Boeing not Westjet has the exemption. Just to keep things correct, you may see other "Boeing" operators doing the same thing.

[New Flyer]

Now this is too much contamination.....

http://www.airliners.net/photo/LOT---Po ... 1671457/L/

[Sasquash]

Excellent job by the F/O in cleaning the windshield with the ice scraper!!!

[Rockie]

Westjet is the only airline in Canada with the exemption permitting frost on top of the wing due to fuel temperature. As mentioned earlier it must be fully contained within an area marked out on the wing, it must not be more than 1/16th of an inch thick (how can you tell from inside?), there must be no active frost or precipitation and the temperature must be above freezing. Very restrictive conditions. No other airline or aircraft other than the 737 has that in Canada.

To answer the original question, beyond the limited case stated above no adhering contamination is permitted...period.

I have taken off with an inch of snow accumulated on the wing, but I had just landed an hour earlier, it was very cold, and the ground crew had gotten on top of the wing with a leaf blower to ensure it would all come off. Which it did about 5 seconds into the takeoff roll. Perfectly legal, and deicing in that circumstance would have made it worse.

[mattedfred]

I have taken off with an inch of snow accumulated on the wing, but I had just landed an hour earlier, it was very cold, and the ground crew had gotten on top of the wing with a leaf blower to ensure it would all come off. Which it did about 5 seconds into the takeoff roll. Perfectly legal, and deicing in that circumstance would have made it worse.

Then why not take the time to allow them to use the leaf blower to blow as much as they can off the critical surfaces?

Are you able to see all of your critical surfaces prior to rotation in order to determine that all of the contaminant has actually blown off?

Why would applying Type I or Type I and IV deice fluid as per the manufacturer's specifications and your Transport Canada Approved Company Ground Deicing Program make it worse? Aircraft can safely and legally operate if these procedures have been followed correctly despite whether they were required or not.

[linecrew]

I have taken off with an inch of snow accumulated on the wing, but I had just landed an hour earlier, it was very cold, and the ground crew had gotten on top of the wing with a leaf blower to ensure it would all come off. Which it did about 5 seconds into the takeoff roll. Perfectly legal, and deicing in that circumstance would have made it worse.

Then why not take the time to allow them to use the leaf blower to blow as much as they can off the critical surfaces?

Are you able to see all of your critical surfaces prior to rotation in order to determine that all of the contaminant has actually blown off?

Why would applying Type I or Type I and IV deice fluid as per the manufacturer's specifications and your Transport Canada Approved Company Ground Deicing Program make it worse? Aircraft can safely and legally operate if these procedures have been followed correctly despite whether they were required or not.

If the aircraft is cold soaked, and the atmospheric conditions are dry (ie. low humidity) and equally cold the snow will not bond to the critical surface. A touch test of certain spots will confirm. Having oodles of de-icing experience with several different companies, I've seen these conditions many times. Nothing is gained by deicing this type of light snow accumulation as it will not alter the aerodynamics of the critical surfaces simply because it won't stay on them. It would just be a waste of time, fluid and money. Having knowledge of what happens in what conditions goes a long way during winter ops and help alleviate the fears that regs seem to instill. Of course if there is ANY doubt in your mind as PIC then absolutely go de-ice, I'm just saying be smart about it.

[Rockie]

I have taken off with an inch of snow accumulated on the wing, but I had just landed an hour earlier, it was very cold, and the ground crew had gotten on top of the wing with a leaf blower to ensure it would all come off. Which it did about 5 seconds into the takeoff roll. Perfectly legal, and deicing in that circumstance would have made it worse.

Then why not take the time to allow them to use the leaf blower to blow as much as they can off the critical surfaces?

Are you able to see all of your critical surfaces prior to rotation in order to determine that all of the contaminant has actually blown off?

Why would applying Type I or Type I and IV deice fluid as per the manufacturer's specifications and your Transport Canada Approved Company Ground Deicing Program make it worse? Aircraft can safely and legally operate if these procedures have been followed correctly despite whether they were required or not.

All this makes perfect sense and was duly considered, but as I mentioned it was cold enough to approach the lowest usable temperature of the deicing fluid. I had a choice of taking off with an absolutely clean wing or one drenched in very cold deicing fluid. Yes it's certified for it, but a clean dry wing is better than one covered in goop. There's also no holdover time clock running, no delay for the passengers, no fuel burning for anything but moving the airplane forward and one less airplane clogging up the deice facility.

It was also a very big airplane, making it totally impractical if not impossible (tail) to actually clean it off with a leaf blower. The groundcrew checked the area over the tanks from front to back including the spoiler panels to ensure no frost formed, which was unlikely since not nearly enough fuel was loaded to make it possible due to cold soak even if the fuel was warm (which it wasn't) , and the wing was almost immediately covered with snow after we hit the gate after landing.

Everybody concerned was satisfied including the most important person (me) that the snow would immediately blow off and there was no underlying contaminate. Had there been the slightest doubt we would of course deiced.

[Apache64_]

Rockie, there are a number of aircraft in Canada other than the 737 that are certified with an allowance for cold soaking in the fuel tank area.

[Rockie]

I didn't know that. What other types are certified to takeoff with frost on top of the wing?

[loopa]

Thanks for the responses.

So it seems to me, that as long as there is an absolute determination that there is no underlying contamination such as frost (unless approved), stuff that will fly off (ie snow), is perfectly acceptable?

Interesting read

http://www.tc.gc.ca/eng/innovation/tdc- ... 9e-768.htm

I was on board another aircraft, temperature was +3 on the ground with moderate rain. We were the only airplane applying CAT4 de ice fluid, while i saw airplanes (of the same company) just line up for take off and off they go. In the climb out we were in cloud until about 30 000 feet.

Ideas?

[aviator2010]

I was on board another aircraft, temperature was +3 on the ground with moderate rain. We were the only airplane applying CAT4 de ice fluid, while i saw airplanes (of the same company) just line up for take off and off they go. In the climb out we were in cloud until about 30 000 feet.

Why do windsheild wipers on airplanes have speed limits?

[Justjohn]

I was on board another aircraft, temperature was +3 on the ground with moderate rain. We were the only airplane applying CAT4 de ice fluid, while i saw airplanes (of the same company) just line up for take off and off they go. In the climb out we were in cloud until about 30 000 feet.

Deice fluid Only works with Ground icing. Type IV is specifically designed to 'sheer' off at 100 Kts. To be clear, It stops working once you are airborne.



Why do windsheild wipers on airplanes have speed limits?


Because they are Most useful on Taxi. I've never found them useful in flight. They are just not very effective. And you just don't need them on anything over approach speeds. The heated windshield is much more effective in keeping precip off. 'Course they make everything fuzzy too

[aviator2010]

I don't think you picked up on the sarcasim there. I was trying to answer his question

[Justjohn]

I don't think you picked up on the sarcasim there. I was trying to answer his question

Sorry Bro, I didn't catch that at all.