LAX91LA182

1991-04-20 · PHOENIX, Arizona, United States · Serious · 1 aircraft · Status: Completed

Aircraft involved

N4066J Robinson R22-BETA Serious

Probable cause & findings

THE PILOT'S FAILURE TO MAINTAIN MAIN ROTOR RPM. FACTOR CONTRIBUTING TO THE ACCIDENT WAS THE PILOT'S INADEQUATE IN-FLIGHT PLANNING.

Factual narrative

THE INSTRUCTOR PILOT ENTERED AN AUTOROTATION WHILE IN CRUISE FLIGHT AT AN ALTITUDE OF 500 FEET ABOVE THE GROUND AND AT AN AIRSPEED OF 60 KNOTS. THE MAIN ROTOR TACHOMETER DECREASED BELOW ITS MINIMAL RANGE FOR FLIGHT WHEN THE HELICOPTER ENTERED THE AUTOROTATION. THE INSTRUCTOR PILOT CONTINUED THE AUTOROTATIVE DESCENT UNTIL PASSING 150 FEET ABOVE GROUND LEVEL BEFORE INITIATING A POWER RECOVERY. THE MAIN ROTOR RPM DID NOT INCREASE AND THE AIRCRAFT COLLIDED WITH GROUND. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12

Verbatim from NTSB's published report. Source file NTSB_1991_LAX91LA182.txt. Findings + structured fields enriched from FAA avall.mdb. Full investigation docket on data.ntsb.gov ↗.

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