Boeing 757 near New York, NY — 2018-09-06

Probable cause

The flight crew’s failure to adequately monitor the airplane’s airspeed, which led to the captain’s aggressive control inputs to increase airspeed; these aggressive inputs resulted in injuries to three cabin crewmembers.

NTSB narrative

The airplane was descending toward the destination airport with the autopilot and autothrottle systems engaged. As the airplane was approaching 12,000 ft, and the autopilot was capturing the altitude, the captain adjusted the altimeter resulting in a displayed altitude of 12,100 ft. The captain (the pilot flying) selected flight level change mode on the autopilot to recapture the altitude and set the speed at 250 knots to slow from about 255 knots. As a result, the autothrottles went to Throttle Hold mode when the throttle levers reached the aft stop. As the captain was briefing the approach, the airplane slowed and pitched up as it tried to maintain altitude with a reduced throttle setting. An international relief officer who was in the cockpit at the time commented on the airplane’s decreasing speed three times when the airplane’s airspeed was about 186 knots before stating that the captain should push the nose over. The captain disengaged the autopilot and auto throttles, aggressively pitched down, and increased the throttles. These aggressive maneuvers caused the flight attendants in the aft galley to be thrown against the ceiling. One flight attendant sustained a compound arm fracture; two other flight attendants sustained minor injuries. The crew subsequently landed the airplane without further incident.

Analysis

Primary failure mode

Automation / mode confusion

First missed decision gate

Disengaging autopilot earlier could have prevented the upset.

NTSB coding

• Abrupt maneuver · Enroute-descent

Evidence available

• CVR
• FDR / data
• 9 docket documents

Docket documents9

• COCKPIT VOICE RECORDER - GROUP CHAIRMAN'S FACTUAL REPORTcvr
• FLIGHT DATA RECORDER - ATTACHMENT 1 (COMPRESSED FDR TABULAR DATA FOR EVENT FLIGHT)fdr
• FLIGHT DATA RECORDER - SPECIALIST'S FACTUAL REPORTfdr
• PILOT/OPERATOR AIRCRAFT ACCIDENT REPORT, NTSB FORM 6120.1form
• STATEMENT OF PARTY REPRESENTATIVESform
• FLIGHT ATTENDANT STATEMENTSinterview
• INTERVIEW SUMMARY - CAPTAINinterview
• INTERVIEW SUMMARY - FIRST OFFICERinterview
• INTERVIEW SUMMARY - RELIEF FIRST OFFICERinterview

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