Hughes OH-6A N66377

Summary

On 29 July 1999 at about 13:15 local time, a Hughes OH-6A registered N66377 was involved in an accident near Aguadilla, United States. One person was 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

29 July 1999 at 13:15

Classification

Accident

Location

Aguadilla, United States

Nearest airport

Unknown

Coordinates

18.4294, -67.1497

Aircraft

Hughes OH-6A

Registration

N66377

Category

Helicopter

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Public Use

Phase of flight

Not recorded

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

MIA99TA206

Nobody was injured.

An unidentified foreign object passing through the oil cooler blower assembly resulting in fracture and seizure of the oil cooler blower, and slowing of the main transmission and main rotor, which resulted in the pilot being unable to arrest the descent during an autorotative landing.

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

Read the full NTSB narrative

While in cruise flight at 800 feet, the pilot heard a metal grinding noise followed by the engine failure warning. The pilot entered autorotation and during landing flare he was unable to arrest the descent, resulting in a hard landing and damage to the helicopter. Postcrash examination of the engine and engine systems showed no anomalies. Examination of the main transmission showed no damage which cause seizing of the transmission. Examination of the oil cooler blower assembly showed one impeller blade was fractured due to overload which opened a two inch gap in the impeller. The blower stopped spinning and sheared away from the adapter. The impeller shroud had abrasion damage and some minor areas of debris buildup. The oil cooler is driven by the main transmission.

Quoted verbatim from the NTSB record.