McDonnell Douglas 369E N991SD

Summary

On 8 October 1999 at about 03:05 local time, a McDonnell Douglas 369E registered N991SD was involved in an accident near Moreno Valley, California, United States. 3 people were on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

8 October 1999 at 03:05

Classification

Accident

Location

Moreno Valley, California, United States

Coordinates

Not recorded

Aircraft

McDonnell Douglas 369E

Registration

N991SD

Category

Helicopter

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Public Use

Phase of flight

Not recorded

Route

Hemet → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Night/Dark

NTSB number

LAX00TA006

Nobody was injured.

The failure of the pilot to maintain sufficient forward airspeed to preclude an inadvertent encounter with loss of tail rotor effectiveness, which resulted in a loss of yaw control. The pilot's failure to initiate timely remedial action is a factor.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

The Sheriff's Department helicopter was orbiting over ground based law enforcement activity. It was a dark night and the winds aloft were 20 to 25 knots at 500 feet agl. The pilot said he was attempting to shine the helicopter's spotlight on a vehicle; however, the wind kept blowing the helicopter past the location on each of the first two orbits. On the third orbit, the pilot inadvertently allowed the helicopter to slow below translational lift speed and the helicopter yawed 180 degrees to the right uncontrollably. The pilot momentarily recovered directional control of the helicopter but then the right yaw resumed. He made several more attempts to recover directional control of the helicopter but when he saw the altitude becoming low, he flew to a pre-selected landing zone where the helicopter landed hard while in a right yawing spin. During the landing the main rotor blades severed the tail boom and the helicopter came to rest on its right side.

Quoted verbatim from the NTSB record.