Pilot Debrief

SCHWEIZER 269C near Springfield, TN — 2023-04-22

Final reportERA23LA205
Sign in to save
Date
2023-04-22
Location
Springfield, TN, USA
Aircraft
SCHWEIZER 269C
Registration
N789LH
Category
Helicopter
Highest injury
None
Fatalities
0
Phase of flight
Descent

Probable cause

A partial loss of engine power for undetermined reasons.

NTSB narrative

After the instructional flight was airborne for slightly more than an hour, the helicopter began descending slightly followed by repetitive low main rotor rpm warnings. The student corrected after the first two warnings, but did not correct after the third. The flight instructor took over the controls and rolled the throttle slightly off, then opened it all the way to the stop, recovering the engine rpm. The flight instructor then initiated a precautionary landing and turned toward an open field. During the descent, when operating in the shaded area of the height velocity diagram (between 100 and 200 ft above the ground and 40 knots airspeed ), the low main rotor rpm again sounded. Knowing the helicopter was flying in the shaded area of the height velocity diagram, the flight instructor nosed the helicopter over to increase airspeed and entered an autorotation. About 40 to 50 ft above ground level (agl), he started a slight deceleration though the helicopter was in a near-vertical descent. He leveled the helicopter at a height of about 10 to 20 ft agl while rapidly approaching the ground. He applied collective to cushion the landing but landed hard, damaging all main rotor blades and the tail boom. Following the accident, the engine was started twice and operated to partial power (due to the main rotor blade damage), with no anomalies noted. The reason for the reported loss of engine power could not be determined from the available evidence.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
PUI could have corrected low MR rpm earlier to prevent descent issues.

NTSB coding

Evidence available

  • 6 docket documents
View NTSB final reportView NTSB docket

Docket documents6

Related mishaps