View Full Version : AC deicing procedure ?

CONF iture
17th Mar 2006, 15:23
For that late evening departure out of YYZ, with no precipitation, we are still at the deicing pad where the deicing fluid type 1 has just been generously applied by a qualified crew who did proceed with the mandatory critical surface inspection when ... on the PA the CAPT advises that part of the new deicing procedure at Air Canada, the FO will go through the aisle to check the wings ...
... what's the story behind that ???!!!

17th Mar 2006, 15:26
Captain had dropped coffee on his shirt and didnt want to be seen in the back???


17th Mar 2006, 15:54
The fully qualified de-icing crew weren't flying the aircaft the Captain was. If thats what he wants that what he gets. In the end he signs to accept the aircraft.

CONF iture
17th Mar 2006, 16:46
If thats what he wants that what he gets
But If you read properly that guy had no choice than following a SOP ... and the question is why suddenly that SOP ?

17th Mar 2006, 17:06
Must be getting standard now, its just come in in our airline.
"The crew must be absolutely sure the surface of the wing is free from contaminates prior to takeoff. And after de-icing a visual inspection must be carried out."
Or something along those lines.

17th Mar 2006, 17:39
Incident in Bos precipated procedure. De-ice crew forgot to spray one wing. Fuel truck was in the way and they neglected to come back and spray remaining wing. Now required to visually check after every spray.

17th Mar 2006, 17:57
I wonder what the ,say RJ146, captain will be supposed to do next?
" Ladies and gentelmen stay relaxed as our FO opens the door and jumps out to verify wings clear of ice. If you, by any chance ,carry on your small private ladder do not hesitate and use to assist him/her to make things faster. thank you"

17th Mar 2006, 18:14
Flew the 146. The best way to see the wing was to open the rear door and look forward.

Dr Illitout
17th Mar 2006, 18:42
Sounds like a damm good Idear to me, both as a pax and as an eng! What better view than through the pax windows and what better judge of de-icing than one of the guys up front!

Rgds Dr I

Lou Scannon
17th Mar 2006, 23:00
SOP or not it is simple commonsense to check that such a vital procedure has been carried out fully. On more than one occasion in my career it hadn't.
All it takes is a quick look out of the door (having made sure that it's disarmed!)
One of those things that used to be called "airmanship".

The Bartender
17th Mar 2006, 23:07
What better view than through the pax windows and what better judge of de-icing than one of the guys up front!

You are joking, right? :bored:

18th Mar 2006, 08:13
The Capt or FO coming back to take a look out the window bothers people? Why?

Hell of a fine idea IMHO! People make mistakes.

It is the Capts responsibility ect. ect. ect :E

Then again maybe it was because there was a "BABE" in row 7.

18th Mar 2006, 10:27
I departed a 744 recently from LHR with icy wings due high inbound fuel load.

Capt asked for deicing crew, but possibly due to comm error between he and I, he neglected to check the procedure had been actioned and pushed back without the deicing being done.

Much red faces as he returned to stand 3 mins later to have the job done - the tug crew pointed out the ice to the capt (well done chaps)

IF they hadn't noticed / realised the seriousness, could have been nasty.

That wouldn't have happened if one of the crew had popped back for a look...

18th Mar 2006, 15:42
You dont specify when the inspection was done. Was it just before takeoff or after the initial de-ice?...if it was just before take-off then it is a requirement if the minimum holdover time has been exceeded that a visual inspection is carried out prior to take-off.
As there is no hold over time for type 1 fluids then this may have come into play.

If it was still at the CDF I dont know.


Few Cloudy
18th Mar 2006, 16:22
It is amazing how well known standard procedures and recommendations get forgotten over the years. What happened to the Clean Aircraft policy and the final responsibility of the Capt?

Who would seriously rather take off while uncertain of clean wing conditions, than risk "worrying passengers"?

I have many times checked the upper surface with Pax on board, following a brief PA to explain what was going on. In my experience Pax are a lot more clever than some crews seem to think, especially if treated with courtesy and given information.

18th Mar 2006, 20:15
Looking through the cabin window will help you notice has the wing been de-iced, but it will not confirm to you is the ice totally cleared. A major hazard is clear ice that is very tough and just about impossible to see even from the cabin window. Someone needs to touch the surface with your hand to be absolutely certain.

Faire d'income
18th Mar 2006, 20:22
Q: What would you say to your company if after exceeding your hold over time and after requesting another de-icing, you were told "we only pay for one de-icing"? ( The implication being you go now.)

It happened. :yuk:

18th Mar 2006, 20:32
One very rare and horrible morning, B737 LHR T4 about 9 years ago with freezing rain, I wanted to see the wing for myself. I got a trolley and climbed up so I was looking down at the Leading Edge. Absolutely clean I thought- I was looking from 18 inches away. I was surprised, I expected something. Just before climbing down, I stroked the bit of wing I had been looking at. Instead of aluminium, it felt rough and icy. A layer of clear ice I couldn't even see from 18 inches away, perfectly transparent! Astonishing. That very morning, an Australian 747 landed and skidded off the runway. Nobody de-iced- the airport was then closed- that freezing rain is deadly!

Always check for yourself. Take it seriously- be a pain in the arse. Get the G/E to bring you a trolley if you have any doubt or anyone persuades you de-icing is not required. They used to whinge if I opened the emergency exit to jump out and see for myself- on more than one occasion I made it clear either I had a feel for myself or someone else took it!

18th Mar 2006, 21:32
Q: What would you say to your company if after exceeding your hold over time and after requesting another de-icing, you were told "we only pay for one de-icing"? ( The implication being you go now.)

It happened. :yuk:

speak to the regulator

Captain Airclues
18th Mar 2006, 22:23

Do you remember that Canadian airfield that we used to transit on the way to Detroit? After several inches of snow had fallen on the wing during the transit, the ground engineer used to come to the flight deck and say "Don't worry cap'n, it'll blow off during the take-off". Of course we politely declined the opportunity to find out!


18th Mar 2006, 23:45
Yes I do! Familiarity breeds contempt. However, if his family were on board, he would have insisted on full de-icing! Funny how not travelling on the aeroplane somehow made tyres 'that's OK Captain!'

19th Mar 2006, 01:45
After de-icing has taken place within my company, we (ground staff), check the wing to make sure the frost or clear ice has totally gone by doing a hands-on check.

It really is the only way to make sure it's all gone.

There are some plonkers out there operating the de-icing equipment for the handling companies !

On a couple of occasions, the fluid temperature wasn't checked before applying it to the wing (it was freezing cold!:uhoh: ) and Mr sprayer was just adding to the problem.

The lack of steam and my hands-on check may have saved the day. :cool:

Obviously for larger aircraft (where you can't get some engineering steps to the wing), the contamination check can't really be performed, only from the window or door, but for the smaller beasts it's fine!

Those of you chaps operating in and out of LHR presently with the current fuel sittuation need to take extra care! Lots of frost and clear ice around!

Safe flying:ok:

19th Mar 2006, 15:24
At LHR indeed we have been warned to take particular care due to fuel situation, when making headset walk around and after and before push back. In parts of the network it seems to be a skill that is all to often left to chance?

19th Mar 2006, 17:19
Yes I do! Familiarity breeds contempt. However, if his family were on board, he would have insisted on full de-icing! Funny how not travelling on the aeroplane somehow made tyres 'that's OK Captain!'

Not if he's pissed off at his wife and kids:)

19th Mar 2006, 21:20
It is a perfectly good practice to check the wing by your self but it's not always possible. Most places we deice the BAe-146 we do it on deicing stands with engines running, so going back and opening the back door to check is not an option! We have to trust the ground staff when they tell us that the deicing of wings and tail is completed.

And by the the way, type I fluid does give you a little bit of hold over time.

The Bartender
19th Mar 2006, 23:43
And by the the way, type I fluid does give you a little bit of hold over time.

Indeed... 0-45 minutes, depending on conditions...

CONF iture
20th Mar 2006, 03:49
Incident in Bos precipated procedure. De-ice crew forgot to spray one wing. Fuel truck was in the way and they neglected to come back and spray remaining wing. Now required to visually check after every spray.
Thank you ... it had to be something behind that !
Any incident report avail ?
Do you know what happened after that, did the aircraft actually take off in that configuration ... ?
I don't know what's the deicing procedure in BOS but apparently it was done at the gate, is it a "in house" deicing procedure, or is it the usual way for BOS ?
I am still surprised AC implemented such a procedure after every spray in a place like YYZ where deicing crew has the authority to verbally certify the airplane is free from any contaminant and if necessary protected against further contaminant. Maybe the deicing crew is not in the aircraft, but I would think they're in a much better position to check these critical surfaces ...
Now, if we follow the same logic, as a passenger, should I complain the Boss didn't send the FO to visually check if the deicing crew didn't forget ... the tail ?!

Faire d'income
20th Mar 2006, 21:48
speak to the regulator
That would be the IAA. :rolleyes:

The Bartender
21st Mar 2006, 00:12
That would be the IAA. :rolleyes:


Well, they could try to pay for only one de-iceing around these parts... "Your flight has been slightly delayed.. ..until may...."

No wonder some airlines have problems with making the holdover-time, with so much paperwork to fill in and exchange with the groundcrew after de-iceing...:ok:

21st Mar 2006, 01:00
Holdover time of course begins at the START of spraying.... once at BHX the holdover time had run out BEFORE the crew had finished.... then they ran out of fluid. We had a lovely breakfast on board, most of our pax did too, then wandered off home. We canx a while later...:)

21st Mar 2006, 15:54
Captain Airclues:

There is a scary CRM video shown to us in Europe. It covers de-icing as well. It was on an F28? and sounds just like your scenario as it was in Canada. The crew were behind schedule. You guessed it, it was snowing, the APU was U/S,, the ground starter was unreliable, there was no de-icing with the engines running (SOP's). A pax, pilot I think, asked the C/A to tell the captain there was a lot of snow on the wings. She went away, returned and said it would blow off on takeoff.
Guess again! Crash!!

It is the captain's legal responsibility to ensure the surfaces are clean. He can delegate this or do it himself. Either way he makes the call. It has been well known in Scandanavia for years that a tactile test is the only 100% sure way, in nasty icing conditions, especially where ice has been present.

There was case recently where Type 1 was ordered and 100% water was used. A/C called back from taxi by the de-ice company. Could have been VERY serious. And not to mention the numerolus incidents/accidents where assymetric ice caused by cold soaked fuel has led to some 'recovery from unusual attitude' demonstrations.

Surely the pax would like to see a sound professional flight preparation. There are already too many dilutions of that on clear sunny days. Let's not allow more to happen in critical situations. Remember the lack of respect/knowledge for icing that might have led to the winter dip in the Potomac.

21st Mar 2006, 21:19
Generally, aircraft anti-ice (note anti-ice, not deice) systems only prevent the ice from forming, they can't remove ice that has already formed, although see the post below for B747 specific operations.

These systems (on jet aircraft) use hot air bled from the engine compressors and feed it through ducts in the leading edges of the wings and engine nacelles. This is becaues the ice tends to start to form on the leading edges and work its way aft, so by heating the leading edges it prevents the initial formation. If the wing is already covered in ice, this leading edge only system won't affect the rest of the wings surface, so the ice needs to be removed before flight. Once cleared and the aircraft is flying, the antiice system prevents new ice forming.

Edited in view of new information posted in the reply below....

Captain Airclues
21st Mar 2006, 22:51
Not strictly true A t.

There is plenty of moisture at high altitudes, as anyone who has had to dodge the Cb's over Africa will confirm. Ice can be a problem at any altitude. However, when the temperature is below -40, the super-cooled ice pellets will not stick to the airframe.

The wing anti-ice system on the 747-400 is actually a de-icer. The technique is to allow an appreciable build up of ice to form and then switch it on, so that the ice breaks away in large chunks. The problem with leaving it on for too long is that the melting ice runs back over the top surface of the wing and then freezes, with no way of removing it.

The wing anti-ice system cannot be used when the flaps are extended as the hot air vents to the atmosphere with the leading edge flaps out. The wing anti-ice system only heats the leading edge, and it is the entire wing which required de-icing prior to take-off.


21st Mar 2006, 22:54
I stand corrected....


Am I still correct in my statement that the ice starts to form at the stagnation point and works aft, or am I just really embarassing myself now??

My background is aircraft engineering based, so my knowledge of how the aircraft are used isn't as good as how they work.

Captain Airclues
21st Mar 2006, 23:28
A t

You are correct. The ice initially forms on the leading edge and then works it's way back.
The problem with using the wing anti-ice before there is an appreciable build up is that the water freezes further back on the wing. By allowing a build up to occur and then switching it on. the ice that is in contact with the wing melts and then the ice breaks away in chunks.


21st Mar 2006, 23:40
Water at temperatures far below freezing point, is very unstable and when disturbed by an aircraft, rapidly changes into clear ice. Air Force research has shown that this rate of ice buildup on an airfoil can be much more rapid than previously thought. In a number of cases, two to three inches of ice developed in less than five minutes. As little as one half inch (1.27cm) of ice can reduce aircraft lift by 50%. As Captain Airclues already stated, the strong convective currents of a cumulo-nimbus cloud develop the large super cooled droplets at those very low temperatures. While an icing layer in the winter may be only about 3,000 or 4,000 feet thick, in cumulo-nimbus the layers may be 20,000 feet in thickness. The freezing level of these convective clouds will be about 15,000 to 18,000 feet AGL and if the cloud top is near 40,000 feet, there is a freezing layer of 20,000 feet or greater.

From an article published in Professional Pilot by Norman Schulyer.

Ignition Override
22nd Mar 2006, 01:42
For the laymen and amateurs out there:
It is clearly stated on our Flight Ops. Manual that after the holdover time for a given temp and precip. condition has elapsed (for one-step or two-step de-icing process), a uniformed crewmember, who is current on the same type of aircraft, can look at the top/leading edge of a wing and if clearly visible (often not enough light), he/she can try to determine whether any precip. has begun to freeze. If any surface condition is in doubt, you return for more de-icing, especially for the two-step process, which has a longer holdover time.

One-half inch of ice is far too much.
Research has proven that even particles as small as medium-grit sandpaper can increase the stall speed a significant amount.
Aircraft with no slats, such as the Fokker 28, DC-9 (-10 series) and CRJ are even more at risk from just "a little ice".
If in doubt, check the NTSB website.

The ATR-42 (American Eagle) turboprop was re-certified after a planeload of passengers and crew smashed into the ground in Roselawn, IN.

Before this tragedy, the US FAA had "allegedly" been notified of serious problems with European ATR-42 aircraft in icing conditions: these experienced 'aileron snatch'-but the FAA "allegedly" did nothing about it until body parts lay on the frozen ground in Indiana.

22nd Mar 2006, 07:25
For a full description of the dangers of icing read the Dryden report.

Brain Potter
23rd Mar 2006, 23:41
A few years ago we had an aircraft that was mistakenly de-iced with hot water. The cabin crew noticed that icicles had formed as the aircraft taxiied to the holding point, informed the captain and perhaps saved the day. Failure to confirm that the airframe was clean was one of the many error made by the crew of the 737 that hit the Potomac bridge. After a de-ice I always have the wings checked by a flight deck crew member before take-off.

Fly Better!
24th Mar 2006, 18:11
Brain, I had a small exec jet de-iced at your home base, the guys there did a great job, there was one guy under instruction and they must have used as much fluid as you would on one of your big birds. He even did under the wing, which was nice :)

I was stood outside watching I got covered as well as the aircraft, the pax had to walk through the stuff so the carpet inside got de-iced too.

Somone once said that no matter how much it costs to de-ice an aircraft its still cheaper than crashing. :ok:

24th Mar 2006, 23:47
An anecdote from ANC 244197;

The flight crew of a US carrier landed at a Russian airport on a scheduled flight only to find that ice had fromed on the upper surfaces of the wings due to fuel cold soak. Perhaps because it was June, the Russian ground crew didn't have de-icing fluid available but they did have another kind of solution- and it worked to absolute perfection.

Tha Captain's story: "...upper wing ice formed due to fuel cold soak. No glycol at airport.....Airport possessed no fluid either.
"So, had Russian ground crew spray wings with hot water, then immediately sprayed 25 bottles of Russian Vodka on top of wings with garden sprayer. Wings were subsequently checked clear of ice. Normal takeoff.":ok:

25th Mar 2006, 15:16
I wonder if Russian vodka in Russia is cheaper than de-icing fluid, too? :D

26th Mar 2006, 20:19
I am surprised?

Ice is one of the biggest killers in our industry but I am getting strong vibes that safety is over ridden by cost?

Is it not the captain who is in charge to inspect the aircraft and sign that he is satisfied that the aircraft is de-iced properly.

The visual check is one and not very reliable but the good old get me hand in it is! (Tactile Check)

I know of some Pilots who put their flasher macks and hi viz on and get of their asses and come out to check.

Other stations do also get their Engineers to do the tactile test for them as this saves time.

I saw a J41 in LBA had a lot of fluid sprayed onto it and visually it looked A1 for flying, I ran my hand over the flaps to find large patches of clear ice?

There are old pilots and bold pilots but never old bold pilots!
(Not talking of the hairless type!):ok: