Figure: J-4101 approach to stall, landing configuration, from NTSB AAR-94/07, Figure 1.

Eddie Sez:

The NTSB gets this mostly right: an inexperienced captain with weak instrument skills flies an unstable approach requiring he reduce his power to idle while on glide slope, fails to notice his speed, and then suspects the first officer did something to cause the stick shaker to go off. When he finally recognized the need for a stall recovery, he pulls back on the yoke and applies less than full power. The NTSB, however, failed to recognize the industry-wide problem of pilots trained to fight for altitude rather than the imperative to break the stall.

But there is one more factor that I think everyone has missed. The captain was known to rely on the autopilot when flying in actual instrument conditions indicating he may have had a weak instrument crosscheck. He arrived at the glide slope too fast and pulled his engines to flight idle and did not notice his speed falling below his target approach speed. When the stick shaker went off and the autopilot disengaged his brain may have been in a panic and reverted to trying to trouble shoot the autopilot and stick shaker rather than accept the airplane was in a stall. More about this: Pilot Psychology / Panic.

What follows are quotes from the relevant regulatory documents, listed below, as well as my comments in blue.


Accident Report


Narrative

[NTSB AAR-94/07, ¶1.1.]

[NTSB AAR-94/07, pages 100 - 102] Cockpit voice recorder transcript


Analysis

[NTSB AAR-94/07, ¶1.5]

[NTSB AAR-94/07, ¶1.16.1]

[NTSB AAR-94/07, ¶2.1]


Probable Cause

[NTSB AAR-94/07, ¶3.2] The National Transportation Safety Board determines the probable cause of this accident to be:

  1. An aerodynamic stall that occurred when the flight crew allowed the airspeed to decay to stall speed following a very poorly planned and executed approach characterized by an absence of procedural discipline;

  2. Improper pilot response to the stall warning, including failure to advance the power levers to maximum, and inappropriately raising the flaps;

  3. Flight crew inexperience in "glass cockpit" automated aircraft, aircraft type, and in seat position, a situation exacerbated by a side letter agreement between the company and its pilots; and
  4. The agreement locked more senior pilots into other aircraft for a minimum period before they could change aircraft, providing opportunity for more junior pilots to fill the captain and first officer positions in the J-4101.

  5. The company's failure to provide adequate stabilized approach criteria, and the FAA's failure to require such criteria.

  6. The company's failure to provide adequate crew resource management training, and the FAA's failure to require such training; and

  7. The unavailability of suitable training simulators that precluded fully effective flight crew training.

See Also

Basic Aerodynamics / Low Speed Flight

Abnormal Procedures & Techniques / Aerodynamic Stall

Normal Procedures & Techniques / Stabilized Approach

Pilot Psychology / Panic

Procedures & Techniques / Crew Resource Management


References

NTSB Aircraft Accident Report, AAR-94/07, Stall and Loss of Control on Final Approach, Atlantic Coast Airlines, Inc. / United Express Flight 6291 Jetstream 4101, N204UE Columbus, Ohio January 7, 1994