Denver Crash Investigation May Take A Year

NTSB Looking At Multiple Factors, But None Jumps Out; 4 Still Hospitalized

(CBS/AP)  Aviation experts say it could take up to a year to figure out what caused a Continental Airlines plane to veer off a runway and slide into a snowy field at Denver International Airport on Saturday, injuring 38 people.

So far, National Transportation Safety Board investigators said they haven't found any problems with the Boeing 737-500's engines, brakes or wheels, but they haven't ruled anything out.

They also haven't released any information about the landing gear under the plane's nose. That gear ended up under the plane, which landed on its belly in a frozen field about 2,000 feet from the runway.

Former NTSB chairman Jim Hall said the complex investigation will look at the condition of the plane's undercarriage, possible wind shifts as the plane sped down the runway and the position of the controls.

Experts say the plane's sudden turn into the wind seems to rule out wind sheer as a factor, reports CBS News correspondent Thalia Assuras.

"The mystery of this flight is did they abort the take-off after something started to happen? Or did they abort the takeoff and then they started to veer off?" former NTSB Managing Director Peter Goelz told Assuras.

Authorities are trying to determine why an odd bumping and rattling noise was heard on the flight's recorders in the seconds before Saturday's crash.

The noise was detected 41 seconds after the jet, bound for Houston, started speeding down the runway. Four seconds later, one of the crew members called for the takeoff to be aborted, said Robert Sumwalt, a NTSB spokesman.

The recording ends six seconds after that, probably because the plane slammed to the ground after hurtling off an embankment, he said.

Tire marks and debris show the plane slid across a grassy strip and a taxiway before going off the embankment, hitting the ground at its base. It then went up a slight hill, over an access road and then down another small hill before stopping.

All passengers and crew members escaped the plane, which caught fire on the right side. Thirty-eight people were injured, including the plane's captain. Four people remained hospitalized Tuesday.

The crew didn't talk on the recording about any problem with wind, which former Department of Transportation inspector general Mary Schiavo said she would expect if a strong crosswind was a factor. Still, she expected investigators to get more detailed information about wind conditions for that particular runway to check out that possibility.

[duh101-2009]

now that i will agree with totally!

[billdefalco-2009]

- And lets not forget to also commend the flight crew - who also played a very key role in carrying out a perfect evacuation sequence where everyone on board was able to get away alive. In any aviation accident the best possible outcome is no deaths of anyone on board and I''m sure everyone on this ill-fated flight is very thankful to have survived it.

[billdefalco-2009]

Keep in mind that the MAJORITY of the aviation accidents and crashes are due to Pilot Error. And so the odds are stacked up heavily against the pilots in this case. In my full time career I am a troubleshooter and a problem solver - not in aviation but is the medical field. But the same method of reasoning used in tracking down the cause of issues can be applied in both areas. My 45-year track record in putting my finger on the cause of issues and problems shows that I''ve been correct better than 99% of the time. So I''m not perfect in my judgment and I very well could be incorrect in my call on this one for sure - but nevertheless it will be most interesting to see what the ultimate outcome of the crash investigation will reveal. Final note - we all make mistakes and no one is perfect and at the very least we still have to commend the pilots for the end result - that everyone on board this aircraft was able to escape and survive this incident.

[duh101-2009]

i marvel at your insight into this matter, and can only guess as to your occupation. any matter of urgent importance will be directed to concerned parties to avoid future incidents, until then due diligence will be the rule of the day. i trust "eye witness" acounts, but you have to take them with a grain of salt. i am amazed and amused by your conjecture, that said, i think you are wrong!

[billdefalco-2009]

More smoking-gun evidence (and why it shouldn''t take a year to figure out) - when the strong wind gust got under the left wing and rolled the 737 to the right - both the right wing tip and right engine struck the ground - this set the right engine on fire. The pilots then realizing their dilemma immediately cut power to both engines as they executed the abort. Therefore, the fuel was cut off to the left engine before it contacted the ground and it was already winding down, but the right engine made ground contact under full power thereby causing catastrophic damage with the input compressor blades striking the cowling and flying debris inside the engine severing fuel lines resulting in the engine fire. They showed a cell-phone video of the right engine fire and it clearly shows the engine fully engulfed in flame from the damage caused by ground contact. Also, take a look of the picture of the aircraft where it came to rest and you can see the right engine casing split open at the bottom where it made ground contact. The left engine tore loose during the slide down into the ravine, helping to slow the craft down in the process. It did not catch fire as the pilots had shut it down before it made contact with the ground.

[billdefalco-2009]

Please note the following correction: making it bank right so much so that they felt the tight wing strike the ground. - It should read: they felt the right wing strike the ground. And by the way - this is a very significant observation. It definitely appears that as the aircraft was just breaking ground, a strong wind gust got under the wing, most pobably because the pilots were not holdiing sufficient (or any) left bank input to hold the left wing down against any possible strong wind gust fron their left during the takeoff roll. (Keep in mind that because of the 5,000 ft airport elevation - the rotation is done at a very low angle - so low that most passengers would not even notice - which is why most of them were not even aware that the craft was actually beginning to lift off the ground).

[billdefalco-2009]

I''m sure the pilots are under a gag order and will absolutely not talk to the press or public - there''s way too much at stake here - their jobs, the reputation of the airline, potential millions in lawsuits, a 75+ million dollar aircraft (unnecessarily) destroyed. I see absolutely no need for it to take a year for the authorities to figure this one out - the smoking gun has already been exposed - the observations of the two passengers from Denver who were seated on the left side and who stated that they felt a strong wind gust shove the aircraft sideways, making it bank right so much so that they felt the tight wing strike the ground. You don''t need a black box to figure this one out and yes - it should show the right bank - followed by the corrections with left rudder and aileron and the hard down abort. The hard impact crushed the gear and as it went over into the ravine, the edge of the ravine tore the crushed gear loose - one sheared off at the top edge (you can see it in the pictures) and the other one went down the hill with the craft. The nose gear wound up under the craft and helped to cushion the slide to the stop.

[buttonjockey]

BillDefalco, You are so much informative than CBS right now! Do we know when the landing gear collapsed? I agree with your theory of crosswinds. Get a plane up to v1 (130 knots on the 737?) and hit it with a 50 knot crosswind and your resultant wind velocity hitting the craft is 140 knots at 21 degrees. That can fly your near wing and leave a large part of the far wing in the shadow of the fuselage, stalling much of it.

So, wouldn''t the flight data recorders have noticed the sudden banking?

Speaking of stalling, I think that also describes the actions of the FAA and the media. BillDefalco, I wonder what it would take to locate the flight crew and passengers and to interview them. That might light a fire under the FAA. Are the pilot''s jobs at risk of they talk?

[billdefalco-2009]

sorry for the double entry - needed to correct typos -

[billdefalco-2009]

I would classify the B-737 as a medium craft in size & weight - in between the smaller and lighter regional jets and the larger and heavier craft such as the B-767 and the A-340 series aircraft. This would make the 737 more susceptible to strong crosswinds than the heavier transport craft since it is lighter and hence has lower inertial mass to resist a sudden positional displacement. Lets not forget the area - mile high Denver in the midst of the mighty Rocky Mountains. Winds in that region are often very strong and unpredictable. They say the wind was 31 kts - but what were the gusts? In windy conditions up there at 5,000 ft in the Rockies - sudden wind gusts of 50 to 70 or 80 kts (and more) are not uncommon and one of those strong blasts could easily displace a B-737 blowing sideways against it during the critical takeoff phase. Once the pilots realized that the right wingtip had struck the ground (probably along with the bottom of right engine as the engines on the 737 are so low slung) they reacted with hard to the left control input and made an emergency abort, putting the craft hard down. This hard correction to the left combined with the hard down abort broke the landing gear and sent the craft into its sliding left trajectory where it slid off the runway and down the embankment. Though they failed to keep downward pressure on the left wing during the takeoff, at least they quickly put the craft back down and came to a stop that enabled all to get off alive.

[billdefalco-2009]

I would classify the B-737 as a medium craft in size & weight - in between the smaller and lighter regional jets and the larger and heavier craft such as the B-767 and the A-340 series aircraft. This would make the 737 more susceptible to strong crosswinds than the heavier transport craft since it is lighter and hence has lower inertial mass to resist s sudden positional displacement. Lets not forget the area - mile high Denver in the midst of the might Rocky Mountains. Winds in that region are often very strong and unpredictable. They say the wind was 31 kts - but what were the gusts? In windy conditions up there at 5,000 ft in the Rockies - sudden wind gusts of 50 to 70 or 80 kts (and more) are not uncommon and one of those strong blasts could easily displace a B-737 blowing sideways against it during the critical takeoff phase. Once the pilots realized that the right wingtip had struck the ground (probably along with the bottom of right engine as the engines on the 737 are so low slung) they reacted with hard to the left control input and made an emergency abort, putting the craft hard down. This hard correction to the left combined with the hard down abort broke the landing gear and sent the craft into its sliding left trajectory where it slid off the runway and down the embankment. Though they failed to keep downward pressure on the left wing during the takeoff, at least they quickly put the craft back down and came to a stop that enabled all to get off alive.

[gowens1]

Job security for some FAA investigators, spend all you can and look important while doing nothing

[rrozsa-2009]

to BillDefalco - Thank you for the highly informative opinion! Would you consider this particular plan to be a small craft, relatively speaking?

[tincup356]

taking peoples word when they are still alive would be too easy and besides passengers might say something they don''t want you to know like what really caused this accident,,,,i thought those little black boxes that cost so much were supposed to be able to survive impact?...guess it was flying too low to work right...yeah right...more overpriced junk from Boeing.

[shanev137]

How about just talking to the pilot and ask him what happened?

[billdefalco-2009]

Here%u2019s my call based on knowledge as a pilot, the available data & observations of the 2 passengers from Denver seated on the left side of the plane & who said they felt a strong wind gust push the craft into a right bank making the right wing strike the ground. This looks like a botched crosswind takeoff to me - failure of the pilots to apply the proper control inputs during a crosswind takeoff. Pilots begin training on small aircraft. Crosswind takeoffs where the wind is blowing directly across the runway are always a challenge - much more for small light aircraft VS heavier aircraft. But a strong wind gust hitting the side of a large transport aircraft on takeoff can have a significant impact on the flight path. Pilots taking off under these conditions must use specific control input to prevent the possibility of a strong wind gust getting under the wind-side wing. In small aircraft this is critical in strong crosswind takeoff conditions & there have been serious crashes where light aircraft have been completely blown over and into the ground. If nothing mechanically went wrong then this incident was probably caused by the failure of the pilots to fully take into account the effect of the strong crosswind conditions present at takeoff. I believe the pilots were complacent about the wind and played down the potential impact of the strong crosswind conditions on their heavy aircraft & therefore did not properly control the aircraft during the take off sequence.