Wednesday, February 3, 2010

Thoughts on Flight 3407, Revisited

It's been nearly a year since the Bombardier Q400 turboprop operated by Colgan Air as Continental Connection Flight 3407 crashed on approach to KBUF with the loss of 50 lives. I had some thoughts that I posted here in May of last year. Now, the NTSB has had a public meeting at which the Board approved a report that lays blame for the proximate causes of the accident at the feet of the crew, particularly the captain. The Board has published "a synopsis from [its] report [which] does not include the Board’s rationale for the conclusions, probable cause, and safety recommendations". The synopsis can be found at this link and makes for very interesting reading.

Back in May I observed that:

"It is looking ever more likely that Capt. Renslow and First Officer Shaw took actions that caused the airplane stop flying. The pressing question is, "Why?" Why did two experienced professional aviators take actions that were so completely wrong?"
The NTSB report synopsis concurs with respect to why the airplane stopped flying, stating in part:
  • "The captain’s inappropriate aft control column inputs in response to the stick shaker caused the airplane’s wing to stall."
  • "The captain’s response to stick shaker activation should have been automatic, but his improper flight control inputs were inconsistent with his training and were instead consistent with startle and confusion."
  • "The captain did not recognize the stick pusher’s action to decrease angle-of-attack as a proper step in a stall recovery, and his improper flight control inputs to override the stick pusher exacerbated the situation."
  • "Although the reasons the first officer retracted the flaps and suggested raising the gear could not be determined from the available information, these actions were inconsistent with company stall recovery procedures and training."
This is an inexplicable set of behaviors from professional aviators. But it seems to me that the vital question remains unanswered: WHY?

Let us stipulate that Capt. Renslow and First Officer Shaw were not a team of the quality of, say, Capt. Sullenberger and First Officer Skiles. Let us also stipulate that they had, by the time the critical moment arrived, introduced contributory factors to the developing Devil's brew: they were not well rested, they were lax in their duty to maintain a "sterile cockpit."

But these factors should not overcome the rule that is programmed into the mind of every pilot from his first hours in training: When the stall warning goes off (and make no mistake, the stick pusher is an emphatic stall warning) you PUSH!. If you PULL you will DIE!

In spite of this deep programming, this Captain PULLED. He pulled HARD, and 50 people died. Why did he do that? The NTSB's synopsis does not provide an answer.

Back in May, I wondered about this:

"...the possible impact on this accident of the well-known and widely viewed NASA Tailplane Stall video. ...The actions of pilots Beck and Renslow in the critical moments...are exactly the prescribed measures for reacting to a tailplane stall and exactly the wrong measures for reacting to an incipient stall of the main wing."
The NTSB first demurs, stating:
"It is unlikely that the captain was deliberately attempting to perform a tailplane stall recovery."
I very much look forward to learning the Board's rationale for that conclusion. Because they go on to say:
"The inclusion of the National Aeronautics and Space Administration icing video in Colgan Air’s winter operations training may lead pilots to assume that a tailplane stall might be possible in the Q400, resulting in negative training."
And they then promulgate the following Recommendation:
"Identify which airplanes ...are susceptible to tailplane stalls and then (1) require operators of those airplanes to provide an appropriate airplane-specific tailplane stall recovery procedure...and (2) direct operators of those airplanes that are not susceptible to tailplane stalls to ensure that training and company guidance for the airplanes explicitly state this lack of susceptibility and contain no references to tailplane stall recovery procedures."
If the first conclusion is supported by the facts, whence the second conclusion and the recommendation?

There are many more conclusions and recommendations in the synopsis of the Board's report. As I said, it makes for interesting reading. And there would appear to be lots more to come (from the NTSB press release on the 2 February public meeting):

"The Board will hold a public forum this Spring exploring pilot and air traffic control high standards. This accident was one in a series of incidents investigated by the Board in recent years - including a mid-air collision over the Hudson River that raised questions of air traffic control vigilance, and the Northwest Airlines incident last year where the airliner overflew its destination airport in Minneapolis because the pilots were distracted by non-flying activities - that have involved air transportation professionals deviating from expected levels of performance.

In addition, this Fall the Board will hold a public forum on code sharing, the practice of airlines marketing their services to the public while using other companies to actually perform the transportation. For example, this accident occurred on a Continental Connection flight, although the transportation was provided by Colgan Air."

These will be interesting proceedings. On the topic of "air transportation professionals" and "expected levels of performance", I recommend highly that you go read this post written by Dr. Tony Kern. It speaks well to this vital topic.


Christine Negroni said...

Hi Frank,
I think you make some very valid points here. It is interesting that the safety board pointed out the error of using the NASA tail plane icing video to train pilots who will be flying an aircraft not prone to tail icing.

Why the pilot and first officer reacted as they did is somewhat less of a mystery when you strip away your characterization that they were
experienced and professional. Very little about the captain indicates professional behavior and his check rides show repeated problems with basic piloting skills. With hundreds of hours on type, he was not a novice, but neither was he notably "experienced"

In writing about the violations of sterile cockpit and the first officer's text messaging from the cockpit, for stories I reported in The New York Times and the Buffalo news, I read and re read the CVR transcript. Its a powerful illustration of crew deficits.

Having said that, it is very important not to crucify this specific crew. Clearly something is very wrong with the safety culture at the airline. The next step has to be to investigate the gulf between safety "policies" and safety practices at the regional carriers. Read more about my thoughts on this at my blog.


starviego said...

The whole official version of what happened is simply not credible. An experienced pilot does not respond to a stall indicator warning by pulling up on the nose at an angle of attack far in excess of even a takeoff climb. Uh uh, something else happened aboard that airplane.

Frank Van Haste said...


Thanks for your input. I guess my feeling is that even a working commercial pilot that ranks in a low quartile on skill sets is unlikely to respond so inappropriately to a stall warning...let alone two such pilots simultaneously. Something really weird happened there and I don't think we understand it...yet.



I also think something else happened on that airplane but I think it happened between the ear-pieces of the two pilots' headsets. We really need to figure it out so that we can fix the (clearly mis-designed) training.

Regards to all,


Dean said...

Hi Frank, I live in Buffalo and actually flew in from Florida hours before 3407 did and there were ice conditions outside but nothing special for us here in Buffalo. I have some aviation experience and have followed the investigation of this crash. Some pilots on other forums made good reference to a n.a.s.a. video about tailplane stalls in which the stalled tailplane forces the stick DOWN and to recover the pilot must pull the stick back and reduce power. I originally thought Capt. Renslow interpreted the stick pusher to be a tail stall even though the dash 8 doesn't seem to be to prone to that. He may have thought it was a tail stall and guessed wrong. Like you and starviego I can't believe he would react to a wing stall by pulling the stick back. Although this is what the N.T.S.B. seems to imply. The N.T.S.B. report also specifically discounts the possibility the pilot interpreted it as a tail stall as posted in line 13 of the report. Frank I totally agree with you on the contradictory info the N.T.S.B. put out in their report. Line 38 of the report which you quoted about winter training for tail stalls makes reference to the importance of not confusing the two. Why add that if they didn't think it was a factor? The N.a.s.a.'s video explains how important it is to feel the difference between a tail or wing stall. A wing stall will shake the airframe where as a tail stall will shake the stick. I can't help but think that Capt. Renslow must have seen that nasa video and interpreted the stick shaker than stick pusher as a tail stall. He should have been flying the plane manually. Although the pilot was probably aware of possible icing I now believe the probable cause was caused by the auto pilot suddenly disengaging as it tried to maintain altitude at low throtle and a possible dirty airframe,followed almost immediately by the activation of stick shaker,than stick pusher and the pilots immediate reaction of pulling than full power which invariably pitched the nose up even more severly. He must have completely lost S.A. long enough so that his actions doomed the flight. Interestingly The N.T.S.B. report mentions little of the pilots reliance on auto pilot when they were at a point in their flight where he should have been flying with the seat of his pants.

Frank Van Haste said...


Thanks for stopping by. I really don't think we've heard the last word about this mishap. Lots of open questions, in my view.


LarryPetro said...

Regarding the strikingly inappropriate responses of Renslow and Shaw to the icing-induced incipient stall, I think it's relevant that: 1) Renslow had previously flown the Saab 340, which does suffer from tail plane stalls, 2) both Renslow and Shaw had been trained by Colgan Air with the NASA icing tail plane stall video, 3) the pilots had discussed their concerns regarding icing conditions during the flight and their lack of experience, and 4) their responses appear to be exactly appropriate for a tail plane stall.

starviego said...

The NTSB report is nothing more than a massive coverup. We can see by reading the reports of the witnesses on the ground that this airplane was obviously in some kind of mechanical trouble right before the crash–

NTSB Dockets, File 431227–witness statements

pg2 of 131
Vicki Braun
plane engine had ”echo sound” then sounded like the engine stopped then heard a ”boom”

pg2 of 131
Hank Cole
plane didn’t sound right, engine sounded like it was ”revving” then cut out and then he heard a bang.

pg 4 of 131 Maha Abdallah
Before the plane impacted the ground, Abdallah noticed sparks coming from the plane.

pg6 of 131
Shannon Alessandra
Just prior to the airplane crashing, the engines made a ”weird sound.”

pg7 of 131
Jean Andreassen
Andreassen stated that she heard strange noises from the engines

pg8 of 131
Kristen and Aaron Archambeault
They both described the engine noise as ‘’sputtering”

pg9 of 131
Stanley Barnas
…he saw a bright orange flash out of the living room window. … After the flash they heard a loud crash. Barnas is 100percent certain the saw the bright orange flash before the crash.

pg11 of 131
Michele Beiter
Michele stated the noise, ’skipped’ and and she was releived it stopped, and then it started again. Michel is positive there was a skip. Michele further described everthing she heard as, ‘Noise, skip, noise, loud noise.’

pg13 of 131
Robert Bijak
The engines sounded like a metallic rattle and remined Bijak of a car engine with no oil in it.

pg14 of 131
Tin Bojarski
The plane did not sound right and sort of sounded like a car with a broken muffler.

pg17 of 131
Ronald Braunscheidel
…he heard a very loud spitting and sputtering sound of a plane engine flying overhead. Braunscheidel described the noise as a car without a muffler.

pg 18 of 131
Sharon Brennan
Brennan believed the plane was… maybe in trouble based on the noise.

pg22 of 131
Patricia Burns
Burns was able to see most of the left side of the airplane and noticed flames coming from the rear of the aircraft.

pg28 of 131
Dan Cizdziel
…heard a sputtering, binging noise to the north….

pg34 of 131
Andrew Dibiase
The rear of the plane appeared to be red, Dibiase could not confirm, but he thought it was on fire.

pg35 of 131
Peter Dibiase
The plane appeared red in color towards the tail of the plane. Dibiase further explained that a bright red glow was reflected off of the yard.

starviego said...

pg42 of 131
Doug Errick
Errick indicated that as the plane got closer the engines became very rough. Errick thought the engines were coming on and off, almost like engines were trying to come back on, but couldn’t remain running. Errick thought the engines were changing RPMs rapidly.

pg49 of 131
Mary Grefrath
Grefrath recalled that the engine sounded like it was spuddering.

pg65 of 131
Dawn Lao
Lao said the engine noise did not sound right… Lao also saw ‘flashes of white light under the wings of the plane….’

pg66 of 131
Jean Larocque
Larocque… stated he heard puttering plane… Larocque reported that the engines were not making a uniform sound.

pg 77 of 131
Molly Merlo
…she heard the airplane make a ”gurgling” sound.

pg81 of 131
Marianne Neri
The engine noise did not sound like a normal plane, but more like a helicopter. It was obvious something was wrong with the engines.

pg85 of 131
Angela Pillo
The sound was very loud and ”rough,” as if the engine was having trouble. The sound was further described as sounding like a ”lawn mower”

pg91 of 131
Lisa Rott
….she heard a consistent low grumbling sound that she believed to be a propeller plane. Rott advised that the sound the plane’s engines was not smooth and did not sound like other propeller planes that she has heard in the past.

pg96 of 131
Kenneth Smith
…heard a big bag then continued to hear the sound of airplane engines.

pg89 of 131
Joseph Summers
…heard a plane which was very low and didn’t sound normal. Mr. Summers cited a ”rambling noise” which sounded as if an engine was not running properly.

pg101 of 131
Rick Telfair
Telfair stated he then heard a winding or grinding noise, then a screeching or grinding noise and approximately 20-30 seconds later heard a large boom… Telfair further described the noise of the engine as fighting, almost as though they were trying to go faster but couldn’t, not accelerating but distressed.

pg 102 of 131
Denise Trabucco
Trabucco described the sound as a humming, similar to a transformer prior to it blowing. Aafter the humming, Trabucco heard a popping sound. … About a minute after the humming and popping sound, Trabucco and her family felt a vibration that felt a little like an earthquake.

pg105 of 131
Lorraine Unverzart
The airplane engines made a ”chugging” sound, similar to a ‘’spark plug misfiring.”

pg106 of 131
Louis Vitello
…he heard the plane engines sputtering as it approached, and then heard a ”poppomg sound.” Immediately after that Mr. Vitello heard ”grinding” noised, stating that the noises reminded him of gears grinding together, sounding like the gears were missing teeth.

pg124 of 131
David Wolf
…the engines were making an unusual ‘’shuttering” sound

pg126 of 131
Melissa Wols
She stated she heard the plane…. grinding and sputtering as it approached and passed over his residence. Wols advised it sounded similar to what grinding metal would sound like.

pg129 of 131
Rita Zirnheld
It ‘’sounded like sputtering” and ”engine was coughing.”

pg130 of 131
She said the plane engine was making loud noises, as though metal was banging and clattering.