Earlier today, the U.S. National Transportation Safety Board (NTSB) released new information from their ongoing investigation of last month's crash of a Colgan Air Dash 8-Q400 near Buffalo. Readers will recall that the aircraft, operating as a Continental Connection flight between Newark and Buffalo, crashed during an instrument approach to runway 23 at the Buffalo-Niagara International Airport on February 12, 2009, killing all 49 people on board, and one person on the ground.We'll get to the new factual information about the aircraft, etc., in a minute, but first, I want to point out something that immediately jumped out at me when I read through today's news release from the NTSB, in which the Board also announced plans to hold a public hearing in Washington regarding this accident. The hearing, which is scheduled for May 12-14, 2009, "will cover a wide range of safety issues including: icing effect on the airplane’s performance, cold weather operations, sterile cockpit rules, crew experience, fatigue management, and stall recovery training," says the NTSB.
Whoa, whoa, whoa! Sterile cockpit rules? What the heck was on that Cockpit Voice Recorder (CVR)? Nothing about the CVR's content -- not even a partial transcript -- has been revealed publicly to date. I can't imagine that they would specifically mention 'sterile cockpit rules' unless there was a reason.
Fatigue management? That phrase gave me a start as well, as did the mention of crew experience and stall recovery training. In fact,I can't help but notice that the "wide range of safety issues" actually is loaded with a wide range of human factors issues. Are you thinking what I'm thinking?
Now, about the aircraft. Today's NTSB update provides the following factual information about Flight 3407:
A preliminary examination of the airplane systems has revealed no indication of pre-impact system failures or anomalies. Investigators will perform additional examinations on the dual distribution valves installed in the airplane’s de-ice system. The de-ice system removes ice accumulation from the leading edges of the wings, horizontal tail, and vertical tail through the use of pneumatic boots. The dual distribution valves, which transfer air between the main bleed air distribution ducts and the pneumatic boots, were removed from the airplane for the examination.Further to the crew issues, the NTSB said:
The airplane maintenance records have been reviewed and no significant findings have been identified at this time.
The ATC group has completed a review of recordings of controller communications with the flight crew during the accident flight and conducted interviews with air traffic controllers on duty at the time of the accident. The group has no further work planned at this time.
Further review of the weather conditions on the night of the accident revealed the presence of variable periods of snow and light to moderate icing during the accident airplane’s approach to the Buffalo airport.
Examination of the FDR data and preliminary evaluation of airplane performance models shows that some ice accumulation was likely present on the airplane prior to the initial upset event, but that the airplane continued to respond as expected to flight control inputs throughout the accident flight. The FDR data also shows that the stall warning and protection system, which includes the stick shaker and stick pusher, activated at an airspeed and angle-of-attack (AOA) consistent with that expected for normal operations when the de-ice protection system is active. The airplane’s stick shaker will normally activate several knots above the actual airplane stall speed in order to provide the flight crew with a sufficient safety margin and time to initiate stall recovery procedures. As a result of ice accumulation on the airframe, an airplane’s stall airspeed increases. To account for this potential increase in stall speed in icing conditions, the Dash 8-Q400’s stall warning system activates at a higher airspeed than normal when the de-ice system is active in-flight to provide the flight crew with adequate stall warning if ice accumulation is present.
Preliminary airplane performance modeling and simulation efforts indicate that icing had a minimal impact on the stall speed of the airplane. The FDR data indicates that the stick shaker activated at 130 knots, which is consistent with the de-ice system being engaged. FDR data further indicate that when the stick shaker activated, there was a 25-pound pull force on the control column, followed by an up elevator deflection and increase in pitch, angle of attack, and Gs. The data indicate a likely separation of the airflow over the wing and ensuing roll two seconds after the stick shaker activated while the aircraft was slowing through 125 knots and while at a flight load of 1.42 Gs. The predicted stall speed at a load factor of 1 G would be about 105 knots. Airplane performance work is continuing.
Since returning from on-scene, the Operations & Human performance group have conducted additional interviews with flight crew members who had recently flown with and/or provided instruction to the accident crew, as well as personnel at Colgan Air responsible for providing training of flight crews and overseeing the management and safety operations at the airline. The group also conducted interviews with FAA personnel responsible for oversight of the Colgan certificate, which included the Principal Operations Inspector (POI) and aircrew program manager for the Dash 8 Q-400. The team has also continued its review of documentation, manuals, and other guidance pertaining to the operation of the Dash 8 Q-400 and training materials provided to the Colgan Air flight crews.By the way, there was some good news about the crew. Toxicology reports were negative for alcohol and illicit drugs for both pilots.
The Operations & Human Performance group continues to investigate and review documentation associated with the flight crew’s flight training history and professional development during their employment at Colgan as well as prior to joining the company.
RELATED: Click here to view all posts about Colgan Air Flt 3407 on Aircrew Buzz.
I'm a little confused about what caused the initial stall response as per the shaker. If I'm understanding the somewhat ambiguous media reports, when an anti-icing system is engaged, the stall speed increases. Therefore, if the aircraft begins a descent under that stall speed threshold, the shaker will activate---even though the aircraft is not technically in a stall. Is that a correct assessment? Further to that, I believe reading that Captain Renslow inputted the wrong approach speeds, perhaps forgetting to account for the stall speed threshold. Then when the sticker activated it would be expected to, he apparently ruled out wing icing, as he had knowingly activated the deicing system. This led to an erroneous conclusion of a tail stall and believing the correct stategy was to pull nose up, Renslow in effect initiated a catastrophic stall and complete loss of control. If anyone can comment on this, I would appreciate it. One has to infer much from the tid bits released by the media.
ReplyDeleteI think the pilot should have pushed the yoke forward instead of back As for the anti-icing system, he should have used it long ago before he got in trouble in the first place. Personally, I would never use an aircraft like that. Most are very old and just waiting for a major failure inflight. I have also seen a Continental Connection aircraft like that, take off and the passenger door open in flight, the chain used as a handrail closest to the prop popped out of the fuselage at the top (still connected to the door at the bottom) and hit the prop. The Captain had to shut down the engine and and return to the airport with the chain dragging on the taxiway and the door wide open. That happened a few years ago at FLL (Ft Lauderdale-Hollywood Intl.)
ReplyDeleteAnon...the Q400 is not an old aircraft and the age of aircraft is irrelevant unless mechanical defect is the cause of a crash. The autopilot was left on and only disengaged when the captain pulled back on the control yoke. Pulling back during a stall warning is the exact opposite of everything a pilot is ever taught. Professional pilots are expected to fly manually in known icing conditions and are expected not to rely on autopilots. The reason for this is that the autopilot is a robot which will faithfully fly an aircraft up until the limit's of that robot's ability. The problem is these robot autopilots can fly an aircraft beyond the capability of a human pilot. If the autopilot is left switched on, then the pilot has no sense that the aircraft is reaching the limits of controlability. Had this approach been performed without autopilot, then there it is likely the approach would have been abandoned successfully, or even perhaps completed successfully. This was entirely caused by poor airmanship. - Simon
ReplyDeletevery bad idea for the copilot to arbitrarily retract flaps at this low airspeed with knowledge of ice on the wings, because the airplane was already woefully 'slow' and the sudden loss of lift with full retraction exacerbated that to the point of no recovery. the crew obviously had never done slow flight stall recoveries in a simulator in this type aircraft, and secondarily, due to their reactions, they were 'toasted' fatigue wise, sealing their fates because they were so utterly whipped.
ReplyDeletetoo many aircrews rely on the autopilots of these machines, which is a very very bad idea in known icing with accretion of ice on the wings to the extent they had already admitted they'd seen. also, going 'full flaps' was a bad idea with that much ice on this machine's wings, that last notch is all 'drag' and very little lift, and they arleady had so much drag it was 'fatal' to them.
ReplyDeletelastly, full flap retraction was indeed a very very very bad idea, gear up was a good idea but taking away all of the flaps this slow was a fatal mistake. pushing the nose down, getting speed back, then doing a proper stall recovery was their best hope, albeit at this altitude, it wasn't likely to work for them too well anyway. far too many crews doing things in the cockpit without understanding the ramifications of those actions (fatal) is a sign of fatigue, and very minimal CRM training in high stress simulations in the sim.
now, do you think the F.A.A. is going to clean up the problem with the 'no rest' situation of these crews? not likely. are the regional carriers going to spend the time to fully train these crews in stall recoveries in severely iced up airplanes like this was? absolutely not. Will another plane of this type go in again for precisely the same combination of reasons? very very likely.
summary: indicting the crew sounds very cool here, but the root cause of this accident was inadequate stall recovery training in type, and inadequate crew coordination or CRM, and probably incredible, mind numbing physical fatigue. Their lives could have been saved, as is true for their passengers, had the F.A.A. been doing it's job and not allowing crews to fly in 'zombie states' because they get INADEQUATE REST!!!!!!!!!!!
the post about the Fed looking the other way when outfits overfly their human rsources is one of the best summaries I've seen on this latest icing event.
ReplyDelete