Southwest Flight 345: Another Unstabilized Approach?

The NTSB today issued a press release yesterday (July 25) regarding the Southwest Flight 345 accident at LaGuardia Airport on July 22. It’s beginning to look like a cause of the accident could be (you guessed it) an unstabilized approach. Here’s the verbatim bullet points from the briefing:

  • Evidence from video and other sources is consistent with the nose-gear making contact with the runway before the main landing gear.
  • The flight data recorder on the airplane recorded 1,000 parameters and contained approximately 27 hours of recorded data, including the entire flight from Nashville to New York.
  • The cockpit voice recorder contains a two-hour recording of excellent quality that captures the entire flight from Nashville to New York and the accident landing sequence.
  • Flaps were set from 30 to 40 degrees about 56 seconds prior to touchdown.
  • Altitude was about 32 feet, airspeed was about 134 knots, and pitch attitude was about 2 degrees nose-up approximately 4 seconds prior touchdown.
  • At touchdown, the airspeed was approximately 133 knots and the aircraft was pitched down approximately 3 degrees.
  • After touchdown, the aircraft came to a stop within approximately 19 seconds.
  • A cockpit voice recorder group will convene tomorrow at NTSB laboratories in Washington to transcribe the relevant portion of the accident flight.

 I can’t do an analysis similar to that we did for Asiana Flight 214, because the FlightAware data stops at 1900 ft altitude. However,  a change in configuration 56 seconds prior to touchdown is certainly indicative of an unstabilized approach.

The briefing from the NTSB suggests that the aircraft was a little bit fast at touchdown, which implies a more nose-down attitude to maintain the required lift. The nose-down attitude, of course, results in the nose touching down first and then collapsing. It’s pretty fundamental that the aircraft should be landed on the mains, so if it does turn out to be pilot error, it’s a pretty basic error, and a good reminder why one should never touch down on the nose wheel first.

Here’s another reminder:

 

Of course, there are exceptions to every rule:

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