Efrem

New information on CO 3407 (Colgan Air):

Complete New York Times article here.

starviego

I am thinking engine problems could have doomed this plane--


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.

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
Barbara Garret
She said the plane engine was making loud noises, as though metal was banging and clattering.





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LarryJ

From the NTSB's list of conclusions:

Loren Pechtel

I could believe the trigger was an engine problem of some kind. After all, something had to slow it down to the speed that triggered the stall warning. An awful lot of crashes are due to pilots reacting wrong to something that would otherwise not have been a big deal.

starviego

More evidence of engine problems before the plane crashed?


File ID 417219 from the NTSB Dockets, ''Powerplant Group field notes,'' does seem to indicate that the left prop may have thrown three 'counterweight' assemblies right before the crash, which may have caused some of the shaft bearings to disintegrate(or vise versa). Remember a few of the ear-witnesses heard a sound like metal grinding on metal.


No 1 engine-

pg2of23
-Three of the six counterweights remained attached to their respective propeller blade outer sleeve, while the other three had become separated and were not recovered by the Powerplant Group.

pg7of23
The No.15 roller bearing, located on the aft side of the bull gear, was present and the cage was fractured with two(2) of the roller elements missing. ...the No.19 roller bearing rolling elements were visible and one(1) roller was missing. ....The No.2.5 roller bearing cage was still attached to the front of the LP shaft. The cage appeared intact but all the roller elements were missing.

pg8of23
The outer diameter of the PT(power turbine) shaft exhibited circumferential rub mark(s) from the fractured end to almost the shoulder where the shaft diameter changes.

pg10of23
The three(3) blade positions sequentially around about the top(as the propellor was situated on the ground) had complete sets of counterweight assemblies(counter weight arm, counterweight, and rear collar) still attached, while the three(3) blade positions that were buried in the ground were missing their complete counterweight assembly.

It should be noted that none of the aforementioned damage was reported for the No.2 engine.


File ID 431227
pg4of131, Maha Abdallah
Before the plane impacted the ground, Abdallah noticed sparks coming from the plane.

They said they never found the missing counterweights. Maybe they should have looked harder--

pg27of131, Mary Cimato
The Cimato's also pointed out three large holes in a pond located behind their house... ... The previous day the entire pond was frozen over, and the morning after the crash they observed holes in the ice.

LarryJ

That "somthing" was the power levers at flight idle, the condition levers at high, the gear down, and the flaps extended to 5, and later 10, degrees.

The stall warning occurred at a higher airspeed than the crew would have expected because they had a speed schedule switch set to increase those warnings (normal for icing conditions) but they set their approach and landing speeds based on a normal (non-icing) schedule.

From the NTSB's list of conclusions:

DenverBrian

So how much of the engines were actually recovered?

starviego

Larry,

I am aware of the NTSB's conclusions. But I think they are lying to protect the carrier or the manufacturer.

A few of the eyewitness accounts were consistent with an engine fire--

File ID 431227

pg9of131, Stanley Barnas
...he saw a bright orange flash out of the living room window. ...Barnas is 100percent certain that he saw the bright orange flash before the crash.

pg15of131, Cindy Borgosz
...saw a bright orange glow through the west window.... the orange glow was not flickering. ....the orange glow diminished, then there was a large boom and an orange 'mushroom cloud.''

pg22of131, Patricial Burns
...noticed flames coming from the rear of the aircraft.

pg96of131, Kaitlin Smith
...she saw a red/orange light in the sky.... after the flash, the sky darkened and then she heard a big bang.

-----------------

All of the engines were recovered, except for the pieces indicated.

------------------

Also of interest is a text message Capt Renslow sent back to dispatch very late into the flight, probably at some point in the descent.

NTSB Dockets File ID 417472

ACARS Report, pg2of3
AIRCRAFT COMMUNICATIONS ADDRESSING AND REPORTING SYSTEM, is mostly a transport network, used to pass short messages back and forth between aircraft and ground facilities. Typically this is the dispatch office of an airline.

A message to ACARS, very late in the flight, is described as

''Uplink-PLEASE ADVICE ME''

Did this mean the pilot was asking advice on a problem with the aircraft as he was descending?

(this message was transmitted 1 hour, 21 minutes after take-off, though the flight only lasted an hour, according to the Flight Data Recorder)



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KCK

If anything is contradictory, it is this analysis. Setting the target airspeed higher would have made a stall even less likely because it should have resulted in the pilot taking action to prevent the stall even earlier. Instead, he took the opposite and wrong action (raised the nose) and stalled the plane. Yes, he was confused, but only because he didn't know what he was doing.

N231LA

I too do not understand the NTSB's conclusion...every pilot knows NOT to pull yoke back when the stall warning goes off...a primary principle of flight. However, the loss of an engine (and a prop problem) in a crucial state of slow flight could have the result of a sudden loss of control.

alanh

Well, the full report hasn't been released yet, which should explain the reasoning behind some of the findings.

As for eyewitness testimony, this article is interesting. 13% of the witnesses interviewed for AA 587 said a wing fell off. Neither wing actually fell off, it was actually the vertical stabilizer.

And there are witnesses in the docket for the Colgan flight that say they saw the plane and there was no fire. Also, a lot of the comments about weird engine noises indicate it was right before the crash. There was around 30 seconds between losing control and the crash when the aircraft would have sounded odd due to the unusual attitudes and low altitude. What would be interesting would be strange engine sounds prior to the upset, which would have shown up on the CVR and DFDR.

As for a cover up, it doesn't really help Colgan all that much to say that it was their badly-performing pilot rather than, say, their badly-performing maintenance engineer. The NTSB hasn't shied against criticizing manufacturers before; why would Bombardier get a pass?

LarryJ

The conspiracy theory is ridiculous. The process is far too open for the conclusions to be doctored without a lot of people calling them on it.

Witness reports are notoriously inaccurate. For example, turbine engines do not "sputter" yet many of the witnesses reported that they did.

The required training maneuver is a recovery from an imminent stall. They are practiced, and demonstrated on every checkride. The procedure is to slow and configure, as appropriate for the type of imminent stall that you are doing, then to initiate recovery at the first indication of a stall which is usually the onset of the stick shaker. The completion standards say that you recover with "minimal altitude loss". In order to complete the maneuver with "minimal altitude loss" it is necessary to maintain a significant amount of back pressure on the yoke to hold the nose of the aircraft well above the horizon. If you allow the nose to drop, as you would want to do in a full-stall recovery, you will lose several hundred feet of altitude and will fail the checkride.

This is an example of a negative transfer of training. The recovery procedure that we use in training is not appropriate in a real-world situation such as the one that the crew of 3407 encountered. The captain was likely fatigued and was certainly surprised and somewhat confused when the stall warning activated, and the autopilot disengaged, at a speed which he thought was an appropriate approach speed for their weight. In the confusion/surprise he did what he was trained to do--hold the nose up to minimize altitude loss.

This wasn't the first crash of a transport category airplane due to a crew incorrectly applying the simulator (imminent) stall recovery procedure to an actual unintentional stall. It's happened several times before and will continue to happen until we change the way we train for stalls.

The digital flight data recorder data has been released. Both engines were at near-full power until impact.

starviego

Unless their badly-performing maintenance engineer warned his badly-performing superiors about the problem, and they told him to get the plane in the air anyway. Then there would be hell to pay. The whole chain-of-command would have been forced to resign, including the founder of the company. They may have even faced criminal charges. No one would have flown their airline again and the whole company would have gone under. It would have shaken all the other feeder airlines too, maybe even have resulted in re-regulation of the entire industry. Wall Street would have been appalled.


http://www.nj.com/news/index.ssf/200...tigators_gathe r_wreckage.html
''....initial reports said the plane was held up due to mechanical problems''
(explaining why the plane took off two hours late from Newark)

http://www.buffalonews.com/home/story/577959.html
(Erie County Executive Chris)Collins said that .... crew members had reported mechanical problems as they approached Buffalo Niagara International Airport.


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alanh

That's a little extreme. There have been crashes due to documented maintenance errors that haven't led to reregulation. Alaska 261 in 2000 is very close to what you suggest -- an tech recommended replacing the jackscrew on the MD-80 but was overruled. Alaska is still in business.

Anyway, the full report will probably mention what the maintenance issue was.