Experts Cite Crosswinds In Denver Crash

Gusts Reached 37 Miles Per Hour On Night Of Crash That Injured 37 People

(AP)  Aviation safety experts said Tuesday strong crosswinds likely were a factor in an accident last month that sent a Continental Airlines jet into a bone-jarring veer off a Denver runway and across open, snowy fields before it came to a halt and caught fire.

Several safety experts raised the possibility that the Boeing 737-500 airliner, carrying 110 passengers, may have experienced "weather vaning," where a strong crosswind pushes a plane's tail and turns the aircraft's nose into the wind, much like it turns a weather vane.

While gusts of up to 37 mph were reported at Denver International Airport on the day of the accident, the experts said, winds were probably not strong enough to explain the accident entirely, and some additional factor - either mechanical failure or human error - also could have played a role.

"My suspicion is that the crosswind was definitely a factor," said Eric Doten, an aviation safety consultant and adjutant faculty member at Embry-Riddle Aeronautical University in Daytona Beach, Fla.

"If there's nothing wrong with the engines and nothing wrong with the gear and nothing wrong with that airplane that they can find, then I would suspect that wind is going to end up being the culprit, and that what happened to the airplane is the result of some reaction to the wind, either by the airplane or by the pilot," Doten said in an interview.

Continental Airlines flight 1404 was taking off for Houston on Dec. 20 when the accident happened, injuring 37 people. The main landing gear was sheared off, its nose gear collapsed, and the plane came down on its belly about 2,000 feet from the runway.

National Transportation Safety Board officials have said the plane's brakes and engines appeared to have been operating normally. Investigators dug the destroyed nose gear out of the ground last week, and safety board spokesman Peter Knudson said preliminary results of that examination may be available later this week.

"We're looking at (crosswinds), but it's just one thing we're looking at," Knudson said. "Nothing is off the table."

One of the puzzles confronting federal investigators is why the jet suddenly turned left off the runway and headed roughly west into gusting crosswinds. Sensors on the runway at the time of the takeoff measured the wind at 31 mph, according to the NTSB, and weather reporting stations on the airport field measured gusts of up to 37 mph.

Spokesmen for Boeing and Continental declined to reveal their guidelines on safely operating the 737-500 in crosswinds. However, Knudson said the winds at the time of the accident should have been "within the envelope" of what the plane could withstand.

Safety experts said the flight's pilots should have been able to compensate for crosswinds.

Doten cautioned that it's still possible there was a mechanical failure involving the nose wheel or some other part, "so you can't say it's definitely a failure on part of the crew to react properly."

NTSB has not identified the plane's pilot, and the Air Line Pilots Association declined to comment.

Former NTSB chairman James Burnett said there's no guarantee that the crosswind safety guidelines are correct for all circumstances.

"It could be that the parameters for crosswinds should be tighter," Burnett said. He noted that the issue seems to be how quickly the pilots reacted "when they first detected some sign of something being amiss," and whether the takeoff should have been aborted as a precaution.

"I don't want to suggest I know the answer to that question, but that's something that's going to be examined," Burnett said.

But John Nance, a former pilot and aviation safety consultant, was skeptical that crosswinds will ultimately be shown to be a cause. He said wind created by the plane's velocity as it gained speed heading north down the runway would have offset the impact of the crosswinds from west.

"It would have taken a mighty burst of wind way, way above anything anybody has recorded in my view ," Nance said.Also, he said, compensating for the type of crosswinds experienced in Denver that day would have been second nature for an experienced pilot, "just like riding a bicycle."

[skydrifter1]

If you examine some of the published pictures, it''s apparent that there were some local snowdrifts, which would account for not only the reported "bumping," but would radically increase the drag on the left main landing gear wheels. Combined with the reported crosswind, it would be enough to cause the ''exit'' rotation.

Add that the ''rise'' of the runway would invoke "Bernouli''s Principle," creating a higher ''local'' cross-wind condition, than the ''reported'' wind.

The key question is whether or not they had enough airspeed to ''yank'' the aircraft off the ground & quickly gain a safe flying speed. However, that''s a major split-second ''judgment'' decision.

In modern aircraft training, the emphasis on technology has led to an abandonment of in-depth "airmanship."

It should be emphasized that without the detailed data from the voice & flight recorders, there is only speculation.

Whether or not the NTSB delivers an honest report is another question.

[rrozsa-2009]

That`s 1 miler per hour, per casualty.
Coincidence?
You be the judge.
-------------------------- Posted by rusure5



Plus, they specifically referred to them as "Cross"winds. And Jesus was hung on a cross. Perhaps it had something to do with their Faith?


-------------------Posted by DaVicar3 at 08:24 AM : Jan 07, 2009

====================

Y''all are cracking me up!

[gliderguy52]

"Spokesmen for Boeing and Continental declined to reveal their guidelines on safely operating the 737-500 in crosswinds. However, Knudson said the winds at the time of the accident should have been "within the envelope" of what the plane could withstand."

The FAA requires that the "Maximum Demonstrated Crosswind Component" (MDCC) be listed in the POH (Pilot''s Operating Handbook), which must be aboard the aircraft for each flight. The MDCC is the maximum crosswind encountered when the aircraft model was first test-flown for certification purposes. Neither the manufacturer nor the FAA set a maximum allowable crosswind component for any aircraft, so it is up to the pilot in command to determine if it is safe to initiate a takeoff. However, many airlines set maximum limits of operation for many parameters of flight, including crosswind operation.

[shanev137]

I''m no expert but a 37mph crosswind doesn''t sound like much for a plane that size.

[rusure5]

Re: "Gusts Reached 37 Miles Per Hour On Night Of Crash That Injured 37 People"

That''s 1 miler per hour, per casualty.

Coincidence?

You be the judge.