the reason to de-ice
A couple of points
1. I am very, very glad that everyone got out of the mess without as much as a scratch.
2. It is beyond any doubt that captain's exceptional skill and level-headness saved everyone once elevator got frozen.
3. Mechanical removal of snow or slush from aeroplane's critical surfaces can be used only as a method of reducing de-icing fluid consumption. It can't be acceptable as a sole de-icing method.
4. During snowfall it is
ly dangerous to take-off without aeroplane being properly anti-iced and/or with hold-over time exceeded. Even if local de/anti-icing facilities leave a lot to be desired, when the wings are not green it is a no-go. Orange wings don't last long in heavy snow and sleet.
5. That there was no explicit warning in Operations manual about de- and anti-icing methods is organizational error which facilitated the crew's error. However, following the somewhat deficient official papers blindly can easily put you in situation described by Richard Bach as: "Everyone else is responsible, you are just the guy that does the dying."
Very sorry to disappoint you BOAC, AAIB report is here. Captain was let down by both his training and his company.
2. It is beyond any doubt that captain's exceptional skill and level-headness saved everyone once elevator got frozen.
3. Mechanical removal of snow or slush from aeroplane's critical surfaces can be used only as a method of reducing de-icing fluid consumption. It can't be acceptable as a sole de-icing method.
4. During snowfall it is
ly dangerous to take-off without aeroplane being properly anti-iced and/or with hold-over time exceeded. Even if local de/anti-icing facilities leave a lot to be desired, when the wings are not green it is a no-go. Orange wings don't last long in heavy snow and sleet. 5. That there was no explicit warning in Operations manual about de- and anti-icing methods is organizational error which facilitated the crew's error. However, following the somewhat deficient official papers blindly can easily put you in situation described by Richard Bach as: "Everyone else is responsible, you are just the guy that does the dying."
Very sorry to disappoint you BOAC, AAIB report is here. Captain was let down by both his training and his company.
Last edited by Clandestino; 9th Oct 2009 at 17:29. Reason: typo
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excrab: Agree. even if you are a 20,000hrs club gang you can oversee certain procedures. You assume that the G/E or handeling agent has done his job. I still have to see the metar for that flight or ATIS, to see the whole picture. Whatīs evedent is that a clean wing, tail and fuselage should be clean under known weather conditions. Donīt know much about the 41 but, it looks like it has some deice-boots? We always learn!!
A little cautionary tale which I've related previously.
We operated B757 aircraft to an airport in Southern Israel.
Our company policy was to carry round trip fuel.
We arrived there in relatively cool, humid conditions.
No surprise when cold fuel caused frost to form on the upper surface of the wings.
I asked for de-icing but there was no de-icing fluid and, in my absence, the handling idiot threw buckets of hot water over the wings. We now had a quantity of ice on the surface which I found aforementioned clown trying to scrape off.
It took some time transferring fuel around and refuelling to melt the ice off.
On return I reported the incident and pointed out that, notwithstanding company 'policy', I would not be taking full round trip fuel in the future.
Thank heaven for a proper airline and BALPA.
We operated B757 aircraft to an airport in Southern Israel.
Our company policy was to carry round trip fuel.
We arrived there in relatively cool, humid conditions.
No surprise when cold fuel caused frost to form on the upper surface of the wings.
I asked for de-icing but there was no de-icing fluid and, in my absence, the handling idiot threw buckets of hot water over the wings. We now had a quantity of ice on the surface which I found aforementioned clown trying to scrape off.
It took some time transferring fuel around and refuelling to melt the ice off.
On return I reported the incident and pointed out that, notwithstanding company 'policy', I would not be taking full round trip fuel in the future.
Thank heaven for a proper airline and BALPA.
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Every time I drive past Pau airport here in South of France, I'm reminded about the need to de-ice. The sorry looking aircraft still sits at the end of the runway on stilts with engines and Air Chance livery removed!
Passengers and crew were lucky to walk away from this one, The driver of the lorry that they hit.. not so.
Passengers and crew were lucky to walk away from this one, The driver of the lorry that they hit.. not so.
I would suggest that accepting a "thumbs up" or any other indication for that matter from ground crew as evidence of satisfactory achievement of de/anti-ice treatment might not always be wise?
In many cases the operatives of the anti/de-ice rigs are simply diverted from a/c cleaning/water/toilet duties to operating the rigs.
As such they may not have the training/experience to make judgemental decisions on ice clearence.
Any signal you get from them simply means they've completed the task.
In many cases the operatives of the anti/de-ice rigs are simply diverted from a/c cleaning/water/toilet duties to operating the rigs.
As such they may not have the training/experience to make judgemental decisions on ice clearence.
Any signal you get from them simply means they've completed the task.
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On many jet opps you have no choice than to accept the deicing crews word. Once the door is shut and the stairs removed you can't just get out and have a look. Even on a small jet, the tail is normaly way too high to look at unless you are in a cherry picker. Many of the airports I fly to in winter have remote deicing. This means you taxi there to get deiced on the way to the take off point, so you have no chance to check over the outside. With the locked door policy, you can't even go in the back to look out of the windows without major hassel.
Seeing the F100 on the page above reminds me of a time when one of my flights almost suffered a similar fate.
I too was an F100 Captain at the time, the aircraft had stood out overnight in snow that had later frozen. The policy was to board passengers, close the doors, remove the bridge, then deice before push. This was all done and we wre holding for a slot. The senior cabin crew member came into the flight deck (pre 2001) and said there was an F/O who was traveling as a passenger in an over wing seat. He asked her to mention his concern to me over ice still on the wing. We had stairs brought to the aircraft and I went outside to check it over. There was so much frozen Ice on the wings we would have probably never been able to fly. We had to deice again, we all lived to fly again and the engineer resposible lost his job.
We still have to rely on staff outside to confirm the job has been done properly, but after that I have always been much more careful who to trust.
Seeing the F100 on the page above reminds me of a time when one of my flights almost suffered a similar fate.
I too was an F100 Captain at the time, the aircraft had stood out overnight in snow that had later frozen. The policy was to board passengers, close the doors, remove the bridge, then deice before push. This was all done and we wre holding for a slot. The senior cabin crew member came into the flight deck (pre 2001) and said there was an F/O who was traveling as a passenger in an over wing seat. He asked her to mention his concern to me over ice still on the wing. We had stairs brought to the aircraft and I went outside to check it over. There was so much frozen Ice on the wings we would have probably never been able to fly. We had to deice again, we all lived to fly again and the engineer resposible lost his job.
We still have to rely on staff outside to confirm the job has been done properly, but after that I have always been much more careful who to trust.
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Phil Capron
Just a short note to question the comment about de-icing above (Feherto post 20).De-icing and anti-icing can be achieved with a one step or two step process depending on fluids available,temperature,precipitation and holdover time reqd. etc. etc.
De-icing is the first stage of a 2 stage process and is never carried out with water but one of a number of recommended fluids usually cold(?)
It is wrong to say de-icing can only be achieved with water.Check it out.
It is also slightly misleading to state whenever you spray a fluid on a wing it is anti-icing.Given the wrong set of conditions/fluid it could seal your fate.
Happy take-offs!
De-icing is the first stage of a 2 stage process and is never carried out with water but one of a number of recommended fluids usually cold(?)
It is wrong to say de-icing can only be achieved with water.Check it out.
It is also slightly misleading to state whenever you spray a fluid on a wing it is anti-icing.Given the wrong set of conditions/fluid it could seal your fate.
Happy take-offs!
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De-Icing Tables, Cold WX Ops
With the advent of the northern winter, it may be timely for all pilots (and maintenance organisations, including contract ground staff) to review their company's cold wx ops; go to:
Holdover Time (HOT) Tables - Commercial and Business Aviation - Airlines & Aviation Operations - Air Transportation - Transport Canada
(it is updated each August - last year it included a section on take-off with PL precip (ice pellets)
Holdover Time (HOT) Tables - Commercial and Business Aviation - Airlines & Aviation Operations - Air Transportation - Transport Canada
(it is updated each August - last year it included a section on take-off with PL precip (ice pellets)
Having had de/anti ice fluid refreeze in the elevator section, I am not necessarily sure that mechanical means of deice are not at times superior. Where dry snow is the contaminant, I would much rather use a broom, ropesaw, leafblower etc.....
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Hi Phil, please read my comment correctly.
1. Water is never allowed as one-step only.
2. Water is allowed as first step in a two-step procedure down to an OAT of -3° C.
3. It must be always observed, by flight crew and ground crew, what is the wing temperature and take it into consideration, when lower as OAT (which is very very often the case and people to not realise it).
4. Every time you spray a fluid on the wings it is a anti-icing. No way out and you must observe hold-over-time,including all requirements (e.g. fluid buffer 7° C for T2/T3/T4 and 10° for T1, 60° C fluid temperature at the nozzle mandatory for T1 and minimum 1 liter per squaremeter.
If you know a case, where it is not an anti-icign having fluid on the wings, please let me know. It would be a brand new thing for me.
Kind regards and have safe flights.
1. Water is never allowed as one-step only.
2. Water is allowed as first step in a two-step procedure down to an OAT of -3° C.
3. It must be always observed, by flight crew and ground crew, what is the wing temperature and take it into consideration, when lower as OAT (which is very very often the case and people to not realise it).
4. Every time you spray a fluid on the wings it is a anti-icing. No way out and you must observe hold-over-time,including all requirements (e.g. fluid buffer 7° C for T2/T3/T4 and 10° for T1, 60° C fluid temperature at the nozzle mandatory for T1 and minimum 1 liter per squaremeter.
If you know a case, where it is not an anti-icign having fluid on the wings, please let me know. It would be a brand new thing for me.
Kind regards and have safe flights.
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de-icing at Newark
25 years ago, I was only a passenger, sitting in a blizzard on the tarmac at Newark N.J. waiting to return to the UK. Some sort of tower with a squirting arrangement started on one wing of the 747. Proceeded in a methodical manner around the aircraft. By the time they had squirted the other wing, I was upset to notice that the first one was now pebbledashed, which didn't seem right. And when they started up and began to taxi, I got very concerned and asked the cabin crew to have a look, the cabin crew got concerned as well, and called for the first officer, who came back and had a good look and said don't worry, dear, there is a de-icing tower just before takeoff. So there was, and in no time we were clear of the snow.
But nobody got out to check on the tail, and I can't imagine aircrew getting out to have a look under normal circumstances. If the ground staff at the airport are disorganised, who can you trust?
But nobody got out to check on the tail, and I can't imagine aircrew getting out to have a look under normal circumstances. If the ground staff at the airport are disorganised, who can you trust?
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Doesn't excatly have to do with the incident which started this thread, but thinking of the CL604 that crashed in Almaty on Dec. 25th 2007, killing the F/O, reminds me of watching very closely whom you can trust and who you shouldn't!
Whatever the personnel in Almaty poured onto the airframe that night was not meant to protect an airplane form ice accretion...
Whatever the personnel in Almaty poured onto the airframe that night was not meant to protect an airplane form ice accretion...
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Jetopa,
where do you have that info from? The bfu hasnīt got anything on this accident (or Ididnīt find it)
I have seen the wreckage in UAAA....
where do you have that info from? The bfu hasnīt got anything on this accident (or Ididnīt find it)
I have seen the wreckage in UAAA....
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BA Airbus Oslo thread continued !
As we enter colder weather I find it odd that the PPRUNE Mods give in so quickly to peer pressure from those who should know better regards airframe icing.
Yes Jet Jockeys tend to experience less of it but ATC can keep you low and slow in less than ideal conditions.
Ice accumulation on the top surfaces of a wing have a huge effect on lift and drag:
Gander : The Untold Story - Canadian Aviation Safety Board Majority Report
"AC 20-117 identifies that the effects of ice formation on an aircraft are wide ranging, unpredictable, and dependent upon individual aircraft design. It states that wind tunnel and flight tests indicate that when ice, frost, or snow, having a thickness and surface roughness similar to medium or coarse sandpaper, accumulates on the leading edge and upper surface of a wing, wing lift can be reduced by as much as 30 per cent and drag can be increased by 40 per cent.
These changes in lift and drag will significantly increase stall speed, reduce controllability, and alter aircraft flight characteristics. It identifies surface roughness as the primary influence in the decrease in lift and increase in drag and emphasizes that take-off not be attempted unless it has been ascertained that all critical components of the aircraft are free of adhering snow, frost, or other ice formations."
It seems the AAIB could not determine how much ice was formed at the time of this incident.
The pilot's were absolutely right to increase approach speed. Buffet WAS felt by the crew.
It is highly likely the greater proportion of ice fell off approaching 500 feet restoring a/c to near normal L/D.
This comment from the AAIB report is mere speculation:
"It is probable that the buffet experienced was due to ice accretion on the top surface of the wings, as suggested by the manufacturer, and was not pre-stall buffet."
It does not state the conclusion was an Airbus Test Pilot's view. It sounds more like a tech person based his V speeds on a clean wing rather than the actual conditions at the time of the approach.
Yes Jet Jockeys tend to experience less of it but ATC can keep you low and slow in less than ideal conditions.
Ice accumulation on the top surfaces of a wing have a huge effect on lift and drag:
Gander : The Untold Story - Canadian Aviation Safety Board Majority Report
"AC 20-117 identifies that the effects of ice formation on an aircraft are wide ranging, unpredictable, and dependent upon individual aircraft design. It states that wind tunnel and flight tests indicate that when ice, frost, or snow, having a thickness and surface roughness similar to medium or coarse sandpaper, accumulates on the leading edge and upper surface of a wing, wing lift can be reduced by as much as 30 per cent and drag can be increased by 40 per cent.
These changes in lift and drag will significantly increase stall speed, reduce controllability, and alter aircraft flight characteristics. It identifies surface roughness as the primary influence in the decrease in lift and increase in drag and emphasizes that take-off not be attempted unless it has been ascertained that all critical components of the aircraft are free of adhering snow, frost, or other ice formations."
It seems the AAIB could not determine how much ice was formed at the time of this incident.
The pilot's were absolutely right to increase approach speed. Buffet WAS felt by the crew.
It is highly likely the greater proportion of ice fell off approaching 500 feet restoring a/c to near normal L/D.
This comment from the AAIB report is mere speculation:
"It is probable that the buffet experienced was due to ice accretion on the top surface of the wings, as suggested by the manufacturer, and was not pre-stall buffet."
It does not state the conclusion was an Airbus Test Pilot's view. It sounds more like a tech person based his V speeds on a clean wing rather than the actual conditions at the time of the approach.
pressure
Lets get back to the good old days (if they ever really existed ?) when safety ruled over commercial pressure & if the weather was bad or icy no one flew. Oops, I had my rose tinted spec's on, back to reality !
I'm very pleased they all landed safely & survived the incident ok, hats off to the crew who, as per usual, performed a professional job under extreme demands.
stay safe folks
I'm very pleased they all landed safely & survived the incident ok, hats off to the crew who, as per usual, performed a professional job under extreme demands.
stay safe folks
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Your Dudeness,
in the examination of the accident that I was referring to, neither the accident investigators of the country where the a/c was registered in (hence the German BFU) nor the Canadians (because it was a Challenger) ever got access to the FDR or voice recorder. They were sent to Moscow.
They were not allowed to take samples of the wreckage either. The de-icing truck was empty, making any analysis of its fluid worthless.
My information comes from people who were actively involved in the accident itself and otherwise directly affected by its outcome. That must be enough.
Lost a friend there. Don't want to capitalize information publicly, but merely share my personal opinion that in the oncoming months it might be a pretty smart idea to watch the people closely who are handling our airplanes and on whom we sometimes have to rely.
in the examination of the accident that I was referring to, neither the accident investigators of the country where the a/c was registered in (hence the German BFU) nor the Canadians (because it was a Challenger) ever got access to the FDR or voice recorder. They were sent to Moscow.
They were not allowed to take samples of the wreckage either. The de-icing truck was empty, making any analysis of its fluid worthless.
My information comes from people who were actively involved in the accident itself and otherwise directly affected by its outcome. That must be enough.
Lost a friend there. Don't want to capitalize information publicly, but merely share my personal opinion that in the oncoming months it might be a pretty smart idea to watch the people closely who are handling our airplanes and on whom we sometimes have to rely.
DeIcing Done Right
On my way back home as SLF I was rerouted through ORD one March evening when the Easterly winds were dumping sticky snow from Lk. Michigan over everything.
The fluid was applied at the gate and was quite thick and warm. Then we joined a conga line to the rwy while the fluid accumlated a layer of snowflakes and came to look like a fuzzy baby's blanket.
Turned on to the rwy and as the a/c accelerated the whole mess slid off like a blanket being pulled away
My only concern was that there must be quite an accumulation of deice fluid sitting on the runway that the gear rolls through and I wonder if the engines take any of it in?
The fluid was applied at the gate and was quite thick and warm. Then we joined a conga line to the rwy while the fluid accumlated a layer of snowflakes and came to look like a fuzzy baby's blanket.
Turned on to the rwy and as the a/c accelerated the whole mess slid off like a blanket being pulled away
My only concern was that there must be quite an accumulation of deice fluid sitting on the runway that the gear rolls through and I wonder if the engines take any of it in?
RatherBeFlying;
This would have been Type IV anti-icing fluid. It is usually green so spray crews can see the areas covered. Its viscosity is high when still but breaks down rapidly under motion and so slides/blows off a surface on takeoff.
Environmental issues are significant, mainly in the de-icing/anti-icing areas such as a centralized de-icing facility. Many have fluid recovery systems but that's a recent innovation.
The Air Canada Pilots Association in Canada held a "Winter Operations" Safety Conference in Toronto at which a great deal of information was presented on these and other winter ops issues.
ANY contamination on a wing is high risk, with outcomes depending upon aircraft configuration, speed, pilot recognition and so on. Hard wings, (no slats/high lift devices) (Bombardier Challenger, CRJ etc) will not tolerate any wing contamination whatsoever.
On takeoff, hard wing (no slats) contamination even by less than a millimeter of frost or mere surface roughness will cause leading edge flow to separate violently, well below the expected stall speed; separation is exacerbated by a snap/fast rotation technique, (> 3deg/sec).
Typically, pilot reaction in all accidents to date was to pull back instead of lowering the nose, sealing the fate of the aircraft. Bank angles at takeoff typically reach upwards of 110deg left or right almost instantly, as shown in available animations of these events.
The key is de-icing, then anti-icing, and where conditions are uncertain, not assuming that there is no contamination. The only way to do that is physical inspection, (not just looking, but hand on the surface).
The fluid was applied at the gate and was quite thick and warm. Then we joined a conga line to the rwy while the fluid accumlated a layer of snowflakes and came to look like a fuzzy baby's blanket.
Turned on to the rwy and as the a/c accelerated the whole mess slid off like a blanket being pulled away
Turned on to the rwy and as the a/c accelerated the whole mess slid off like a blanket being pulled away
Environmental issues are significant, mainly in the de-icing/anti-icing areas such as a centralized de-icing facility. Many have fluid recovery systems but that's a recent innovation.
The Air Canada Pilots Association in Canada held a "Winter Operations" Safety Conference in Toronto at which a great deal of information was presented on these and other winter ops issues.
ANY contamination on a wing is high risk, with outcomes depending upon aircraft configuration, speed, pilot recognition and so on. Hard wings, (no slats/high lift devices) (Bombardier Challenger, CRJ etc) will not tolerate any wing contamination whatsoever.
On takeoff, hard wing (no slats) contamination even by less than a millimeter of frost or mere surface roughness will cause leading edge flow to separate violently, well below the expected stall speed; separation is exacerbated by a snap/fast rotation technique, (> 3deg/sec).
Typically, pilot reaction in all accidents to date was to pull back instead of lowering the nose, sealing the fate of the aircraft. Bank angles at takeoff typically reach upwards of 110deg left or right almost instantly, as shown in available animations of these events.
The key is de-icing, then anti-icing, and where conditions are uncertain, not assuming that there is no contamination. The only way to do that is physical inspection, (not just looking, but hand on the surface).