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icing accident

Old 8th Aug 2011, 14:37
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icing accident

Hi guys,

I recall some time ago I was told that an aircraft had an accident due to airframe icing..

Basically the captain was in the queue for takeoff and he went very close to the aircraft preceding him so as to use the warm air going out of the preceding aircraft's engines to melt down the ice..

And then he crashed when trying to get airborne!

Do you have any more details on this?

Thanks in advance!
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Old 8th Aug 2011, 16:58
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Likely only a rumor

Unnless one can find those words in a AAIB, BEA, NTSB report.

Nevertheless, many accidents have happened due to icing and casual attention, so the lessons learned are already known.
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Old 8th Aug 2011, 17:11
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Asddsa

Sounds like accident you are thinking of may the 737 that crashed into the Potomac. I can't recall, someone will, the carrier but I think they were based in Florida and the accident occurred when they took off with icing on the wings. My guess it was the mid 80s.

rgds

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Old 8th Aug 2011, 17:32
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Sounds like accident you are thinking of may the 737 that crashed into the Potomac. I can't recall, someone will, the carrier but I think they were based in Florida and the accident occurred when they took off with icing on the wings. My guess it was the mid 80s.
I'm pretty sure that is the accident in question. However, airframe icing was not the direct cause of the accident. The real cause of the accident was that the ERP probes in the engine inlet did become clogged/obstructed with ice, causing the ERP gage to give false readings.

So when max power was set, the actual power of the engine was around 78%* not 100% due to the false readings.

The real tragic thing about this accident is, at any point before they hit the bridge, if they had firewalled the engines, they would have avoided the accident.

In the cockpit voice reorder the co-pilot (PF) can be heard asking the captain if the power setting are correct, at least two times.



* Going from memory on that, to lazy to look up the actual figure.
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Old 8th Aug 2011, 18:20
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There is complete CVR ...but I can not find it now.
Plane crashes into Potomac — History.com This Day in History — 1/13/1982
 
Old 8th Aug 2011, 18:54
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Bad copy, but http://libraryonline.erau.edu/online...s/AAR82-08.pdf

CVR transcript CVR Transcript for the Crash of Air Florida Flight 90
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Old 8th Aug 2011, 18:59
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Thanks guys, really appreciate that!!


here is what I was looking for:


Adding to the plane's troubles was the pilots' decision to maneuver closely behind a DC-9 that was taxiing just ahead of their aircraft prior to takeoff, due to their mistaken belief that the warmth from the DC-9's engines would melt the snow and ice that had accumulated on Flight 90's wings. This action — which went specifically against flight manual recommendations for an icing situation — actually contributed to additional icing on the 737. By sitting behind the preceding aircraft, the exhaust gases melted the snow on the wings. During takeoff, instead of falling off the plane, this slush mixture then froze on the wings' leading edges and the engine inlet nose cone.
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Old 8th Aug 2011, 19:43
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@asddsa: The FSF's Aviation Safety Network Database lists some 161 "Icing" related events so if you were so inclined you could scan through those to see if any met the rough description you have.

I tend to agree with lomapaseo that this is likely rumour, but with some grains of truth. OK, more than rumour! My apologies for my scepticism

One element is that a number of icing accidents on takeoff have occurred where crews have (incorrectly) assumed that 'loose snow' on the wings would blow off, only to find out far too late that there's a layer of ice under the snow which seriously degrades the wing performance. In those cases it's not been the efflux of another aircraft but rather their own takeoff roll that was assumed would do the blowing off.

A second is that the AAIB report into the Challenger 604 accident at Birmingham England included an investigation into the effect of APU exhaust on possibly melting some of the frost believed present on the wings. The report concludes that there may have been some effect of such melting, but my own opinion is that it probably had little impact on the accident itself.

Last edited by Mad (Flt) Scientist; 8th Aug 2011 at 19:44. Reason: new info in preceding post
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Old 9th Aug 2011, 08:35
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Aviation Today :: Ice Contamination Accidents On Takeoff Reach Epidemic Proportions

But I seem to remember that there was a TP behind a BAe 146 that had one wing heated and the other one contiminated but I can't find a reference. I can't remember if it was a type IV gelling issue or that they rolled on departure.

Last edited by mad_jock; 9th Aug 2011 at 08:49.
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Old 10th Aug 2011, 15:12
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Some years ago in FRA, queuing for rwy 18 in freezing conditions, we noticed the aircraft in front of us appeared to be accumulating a heavy layer of ice on the trailing edge of the inner portion of the wing. There was no doubt the aircraft had been de-iced as the foam was visible dripping in several places. We surmised that the ice was forming due to the light snow falling at the time being melted in the jet exhaust and then settling on the cold wings. The tailwind as we taxiied down to 18 was about 15-20 knots, enough to send the exhaust gas back over the wing.
We advised the crew of the situation only to be told they were happy as they had been de-iced and had another 10 mins of hold-over time. We watched as they took off but lost sight of him about 1500m down the runway in the driven snow. We feared the worst and said so to each other, sure that we would see a fireball in the gloom.
My FO flicked over to the departure frequency and heard them call in, much to his relief, but then concern when ATC asked him to verify his altitude was 200 feet! My guess is that he should have been around 1000' at that point.
We returned to the ramp and had the half inch of solid ice removed from the rear half of our wing. It stopped snowing soon afterwards.
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Old 10th Aug 2011, 21:10
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mad jock

yes that happened at CDG, the crew sat behind the 146 saw the problem and called it out, from recollection (I worked for the 146 operator at the time) one side of the aircraft had been de-iced with a mix of 100% water due to an equipment problem.
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