Schweizer 269D N255TP

Summary

On 19 February 2004 at about 08:45 local time, a Schweizer 269D registered N255TP was involved in an accident near San Antonio, Texas, United States. 2 people were on board and 2 had minor injuries. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

19 February 2004 at 08:45

Classification

Accident

Location

San Antonio, Texas, United States

Coordinates

29.3394, -98.4742

Aircraft

Schweizer 269D

Registration

N255TP

Category

Helicopter

Engines

1

Operator

Not recorded

Operating rule

Public Use

Purpose of flight

Public Use

Phase of flight

Not recorded

Route

San Antonio → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Night

NTSB number

FTW04GA076

2 people had minor injuries.

The loss of engine power due to the axial movement of the compressor rotor blades contacting the compressor vanes resulting in a subsequent compressor stall. A contributing factor was the improper assembly of the compressor section during the engine overhaul by unknown maintenance personnel.

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

Read the full NTSB narrative

The 493-hour pilot reported that approximately 5 minutes after departure, he noticed a "slight change in engine noise." Subsequently, he heard a "bang," followed by an aural engine warning horn, and a loss of engine power. The pilot initiated an autorotation, and during the autorotation, the helicopter impacted power lines, landed hard on a parking lot surface and came to rest upright. A witness located adjacent to the helicopter's flight path reported hearing a "loud backfire" followed by subsequent white smoke coming from the helicopter. Review of the aircraft maintenance records revealed the engine was overhauled approximately 295 hours prior to the accident. During the engine overhaul, the impeller travel (bump clearance) was measured to be approximately .010 inches. During the engine teardown examination, prior to the removal of the compressor rotor from the rear support, the impeller travel (bump clearance) was measured to be approximately 0.021 inches. The third, fifth, and sixth stage vane assemblies were bent in the direction of rotation. Corresponding damage was observed on the trailing edges of the blades on the adjacent forward compressor rotors. Fretting and score marks noted on the compressor assembly components were consistent with axial movement at the compressor assembly resulting in contact between the compressor blades and vanes, and a subsequent compressor stall and loss of engine power.

Quoted verbatim from the NTSB record.