Enstrom F-28A N9573

Summary

On 23 August 2004 at about 14:50 local time, a Enstrom F-28A registered N9573, operated by P & N Corporation, was involved in an accident near Leroy, Minnesota, United States. One person was on board and one was seriously injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

23 August 2004 at 14:50

Classification

Accident

Location

Leroy, Minnesota, United States

Coordinates

43.8875, -92.8431

Aircraft

Enstrom F-28A

Registration

N9573

Category

Helicopter

Engines

1

Operator

P & N Corporation

Operating rule

Part 91: General Aviation

Purpose of flight

Aerial Observation

Phase of flight

Not recorded

Route

Leroy → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

CHI04CA237

1 person was seriously injured.

The partial loss of engine power due to the missing 1/8-27 NPT Allen plug as a result of other maintenance personnel undertorquing the plug. Additionally, the pilot improperly excecuted a run on landing. A factor was the loss of tail rotor effectiveness.

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

Read the full NTSB narrative

The helicopter sustained substantial damage when it impacted terrain and rolled over after a loss of engine power during takeoff. The pilot reported that the engine was producing 3,000 rpm's when he brought the helicopter into a hover. He transitioned into forward flight and cleared a fence, and then the engine lost power. He reported that he thought that an exhaust valve was stuck. He attempted to do a run on landing to a field. The helicopter touched down on its left skid two times but the helicopter was not straight. He reported that the third time the helicopter touched down on its left skid, the helicopter was not straight and the rpm's were low. He reported that he ran out of tail rotor authority. The helicopter rolled over on its left side. The engine was inspected and an engine run was conducted. The engine was run at 1,800 to 2,000 rpm, and then at 1,110 to 1,200 rpm; but the engine popped and ran unevenly. A re-inspection of the engine revealed that the 1/8-27 NPT Allen plug to the number four cylinder was missing. Once the hole was plugged, the engine ran smoothly.

Quoted verbatim from the NTSB record.