Frozen in flight EGL 4184 (roselawn)
06-08-2009 | 08:35 AM
#11
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From: RJ Captain
The icing boots were extended shortly after the accident and the plane can take icing conditions.
It was not all design flaw that brought that flight down. Holding below minimum recommended icing holding speed did not help matters any. It was your usual "series of events" that ultimately led to the crash.
The planes were sent south, but they are back in DFW now, where there is significant icing possibilities. And many operators continued to fly the ATR in extreme northern climates. I think the transfer south was part for public perception and part to make way for RJs.
It was not all design flaw that brought that flight down. Holding below minimum recommended icing holding speed did not help matters any. It was your usual "series of events" that ultimately led to the crash.
The planes were sent south, but they are back in DFW now, where there is significant icing possibilities. And many operators continued to fly the ATR in extreme northern climates. I think the transfer south was part for public perception and part to make way for RJs.
Yes the accident was a chain of events. Holding -or flying -for any length of time in Icing conditions at slow speeds with the autopilot on may not be very smart.
06-09-2009 | 05:25 AM
#13
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From: CRJ FO
I'm going on memory here, as I read the book around 10-12 years ago. At the time I believe they were operating at the recommended speeds. After the accident I believe they were increased. There had been several incidents and at least one other icing related accident where Ice was suspected to have formed behind the boots. If ATR had stepped up after the accident in Italy and said they wanted to make changes to the boots and increase speeds at that time, the Roselawn accident may never have happened.
Yes the accident was a chain of events. Holding -or flying -for any length of time in Icing conditions at slow speeds with the autopilot on may not be very smart.
Yes the accident was a chain of events. Holding -or flying -for any length of time in Icing conditions at slow speeds with the autopilot on may not be very smart.
I was told at the school house that Eagle always recommended 180 as minimum for icing hold speeds. That could be true or false. But having the autopilot on was not a good decision.
Why do so many people have to die before they decide to redesign critical elements to an aircraft anyhow? (Pitot tubes comes to mind at the moment).
06-09-2009 | 06:28 AM
#14
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From: 737 CA
I flew ATR's in the NorthEast for years. I read the book; great science fiction. The icing that brought that ATR down was very severe and NO airplane has ever been certified to fly in it. They were not aware to their conditions. The CA was back talking to the FA. The FO was listening to rock on the ADF. They were too slow and used flaps in holding to keep the deck angle down (putting more ice behind the boots). Sure they made improvements to the ATR's ice ability after the accident- they could do that with any plane. Read the actual NTSB report and not some disgruntled pilot's book.
06-09-2009 | 08:26 AM
#15
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From: Captain, CRJ-200, ASA
ATRs do fine in ice as long as the pilot is smart about it... just like any other airplane. You have to escape the conditions at the first signs of severe ice. Of course, our training on icing has changed significantly for ATRs post Roselawn.
I got so much ice on an ATR-72 once, I had a 4 inch rams horn on the ice indicator probe. She flew fine, but you'd better bet your life we ran the severe ice procedure and got the hell out of it asap!
In Roselawn, I think it was indeed a chain of events. An airplane that had boots that were too small and a tendency to develop aerodynamic flow distortions over the control surfaces in ice accretion (unknown at the time). A lack of training in icing procedures and severe icing escape guidelines for the pilots. And finally, inattention by the pilots to their deteriorating condition, as they held for an extended period, in freezing rain, at flaps 15.
I got so much ice on an ATR-72 once, I had a 4 inch rams horn on the ice indicator probe. She flew fine, but you'd better bet your life we ran the severe ice procedure and got the hell out of it asap!
In Roselawn, I think it was indeed a chain of events. An airplane that had boots that were too small and a tendency to develop aerodynamic flow distortions over the control surfaces in ice accretion (unknown at the time). A lack of training in icing procedures and severe icing escape guidelines for the pilots. And finally, inattention by the pilots to their deteriorating condition, as they held for an extended period, in freezing rain, at flaps 15.
06-09-2009 | 08:58 AM
#16
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From: retired
In Roselawn, I think it was indeed a chain of events. An airplane that had boots that were too small and a tendency to develop aerodynamic flow distortions over the control surfaces in ice accretion (unknown at the time). A lack of training in icing procedures and severe icing escape guidelines for the pilots. And finally, inattention by the pilots to their deteriorating condition, as they held for an extended period, in freezing rain, at flaps 15.
06-09-2009 | 03:42 PM
#17
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I flew ATR's in the NorthEast for years. I read the book; great science fiction. The icing that brought that ATR down was very severe and NO airplane has ever been certified to fly in it. They were not aware to their conditions. The CA was back talking to the FA. The FO was listening to rock on the ADF. They were too slow and used flaps in holding to keep the deck angle down (putting more ice behind the boots). Sure they made improvements to the ATR's ice ability after the accident- they could do that with any plane. Read the actual NTSB report and not some disgruntled pilot's book.
N401AM was only in icing conditions for 5 minutes out of the last 15 minutes of flight (primarily only in the outbound leg at LUCIT). Those conditions were indeed outside the certification of the aircraft, but NOT for accretion rate (common "severe ice" criteria), but for the type of icing that was occuring. This type of icing "super-cooled droplets" or SCD was insideous and not easily identified at the time. The deice boots were inadequate in size to prevent ice accretion aft of them, especially in their configuration (holding flaps 15). A configuration approved by the airline and manufacturer, by the way as it was the only way to stay below maximum holding speed for that aircraft. "Chatter" and "rock music" were not significant part of the accident, although the French (in typical fashion) attempted to find something else to blame instead of their design problems and highlighted these.
This aircraft had design issues with the wing and deice system that were the DIRECT and primary cause of this accident. Believe what you want, but those are the facts.
06-09-2009 | 06:31 PM
#19
Tuk er jerbs!
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From: B747 Left
There's a lot of conjecture on this accident in this thread for some reason...let me save some trouble. 
Originally Posted by NTSB
The National Transportation Safety Board determines the probable cause(s) of this accident as follows:
the loss of control, attributed to a sudden and unexpected aileron hinge moment reversal that occurred after a ridge of ice accreted beyond the deice boots while the airplane was in a holding pattern during which it intermittently encountered supercooled cloud and drizzle/rain drops, the size and water content of which exceeded those described in the icing certification envelope. The airplane was susceptible to this loss of control, and the crew was unable to recover. Contributing to the accident were: 1) the French Directorate General for Civil Aviation's (DGAC's) inadequate oversight of the ATR 42 and 72, and its failure to take the necessary corrective action to ensure continued airworthiness in icing conditions; and 2) the DGAC's failure to provide the FAA with timely airworthiness information developed from previous ATR incidents and accidents in icing conditions,3) the Federal Aviation Administration's (FAA's) failure to ensure that aircraft icing certification requirements, operational requirements for flight into icing conditions, and FAA published aircraft icing information adequately accounted for the hazards that can result from flight in freezing rain, 4) the FAA's inadequate oversight of the ATR 42 and 72 to ensure continued airworthiness in icing conditions; and 5) ATR's inadequate response to the continued occurrence of ATR 42 icing/roll upsets which, in conjunction with information learned about aileron control difficulties during the certification and development of the ATR 42 and 72, should have prompted additional research, and the creation of updated airplane flight manuals, flightcrew operating manuals and training programs related to operation of the ATR 42 and 72 in such icing conditions.
the loss of control, attributed to a sudden and unexpected aileron hinge moment reversal that occurred after a ridge of ice accreted beyond the deice boots while the airplane was in a holding pattern during which it intermittently encountered supercooled cloud and drizzle/rain drops, the size and water content of which exceeded those described in the icing certification envelope. The airplane was susceptible to this loss of control, and the crew was unable to recover. Contributing to the accident were: 1) the French Directorate General for Civil Aviation's (DGAC's) inadequate oversight of the ATR 42 and 72, and its failure to take the necessary corrective action to ensure continued airworthiness in icing conditions; and 2) the DGAC's failure to provide the FAA with timely airworthiness information developed from previous ATR incidents and accidents in icing conditions,3) the Federal Aviation Administration's (FAA's) failure to ensure that aircraft icing certification requirements, operational requirements for flight into icing conditions, and FAA published aircraft icing information adequately accounted for the hazards that can result from flight in freezing rain, 4) the FAA's inadequate oversight of the ATR 42 and 72 to ensure continued airworthiness in icing conditions; and 5) ATR's inadequate response to the continued occurrence of ATR 42 icing/roll upsets which, in conjunction with information learned about aileron control difficulties during the certification and development of the ATR 42 and 72, should have prompted additional research, and the creation of updated airplane flight manuals, flightcrew operating manuals and training programs related to operation of the ATR 42 and 72 in such icing conditions.
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