Day: March 6, 2015

Dark, snowy, limited visibility, slick runway, short runway, inadequate safety areas, all ingredients for a disaster. The data must be analyzed but based on our litigating these accidents before here is what must be carefully looked at.

This is an old airplane with lots of time on it. The aircraft swerved after making a normal landing. Although it came out of a recent inspection crew write ups on thrust reversers and engine spool up times need to be examined for differences between the left and right engines. The auto-braking system and antiskid must likewise be examined.

Why, because a similar accident occurred with an American Airlines MD-80 in a thunderstorm.

In the American crash, when the crew deployed thrust reversers the buckets did not deploy symmetrically. The engines spooled up 11 seconds apart so as the power came up the airplane skidded sideways. Sound familiar?

In addition the brakes were also problematic so the airplane went sideways down the runway until the crew could straighten out the airplane before it left the runway. The wing spoilers did not deploy even though armed. Ten were killed.

If the braking is not symmetric, i.e. equal left and right the airplane can skid sideways New Crash Likely Old Problem
Delta Airlines crash at La Guardia Could Have Been a Lot Worse

Dark, snowy, limited visibility, slick runway, short runway, inadequate safety areas, all ingredients for a disaster. The data must be analyzed but based on our litigating these accidents before here is what must be carefully looked at.

This is an old airplane with lots of time on it. The aircraft swerved after making a normal landing. Although it came out of a recent inspection crew write ups on thrust reversers and engine spool up times need to be examined for differences between the left and right engines. The auto-braking system and antiskid must likewise be examined.

Why, because a similar accident occurred with an American Airlines MD-80 in a thunderstorm.

In the American crash, when the crew deployed thrust reversers the buckets did not deploy symmetrically. The engines spooled up 11 seconds apart so as the power came up the airplane skidded sideways. Sound familiar?

In addition the brakes were also problematic so the airplane went sideways down the runway until the crew could straighten out the airplane before it left the runway. The wing spoilers did not deploy even though armed. Ten were killed.

If the braking is not symmetric, i.e. equal left and right the airplane can skid sideways on a slick runway. if the reverse buckets don’t deploy symmetrically the airplane can skid sideways on a slick runway, if the engines do not spool up symmetrically ( and they rarely do) the airplane can skid sideways on a slick runway. Before blaming the Delta flight deck crew, which no doubt will happen, the NTSB needs to look at these issues and also check to see if there were any prior complaints by other crews of anomalies with these systems on this aircraft. A careful check of approach airspeeds and deployment of the spoilers on the wings after touchdown must also be verified. The spoilers on an MD-80, necessary to put weight on the wheels for more effective braking, must be armed by the flight deck crew for them to deploy. The pre-landing checklist must be verified on the Cockpit Voice Recorder. There is a distinctive clunk sound arming that system makes.

La Guardia can be challenging, especially at night in a snowstorm. Plowing is useful but in the midst of a very heavy snowstorm may not be enough. The runways are short, there is water everywhere but thankfully no one was seriously hurt and other than embarrassment life will go on.

Arthur Alan Wolk

March 6, 2015

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