Aerovodochody L-29 DELFIN N37KF

Summary

On 18 June 2011 at about 21:50 local time, a Aerovodochody L-29 DELFIN registered N37KF, operated by Ward Raju Mann, was involved in an accident near Reno, Nevada, 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

18 June 2011 at 21:50

Classification

Accident

Location

Reno, Nevada, United States

Nearest airport

Reno-Stead (4SD)

Coordinates

39.6672, -119.8761

Aircraft

Aerovodochody L-29 DELFIN

Registration

N37KF

Category

Airplane

Engines

1

Operator

Ward Raju Mann

Operating rule

Part 91: General Aviation

Purpose of flight

Air Race/Show

Phase of flight

Not recorded

Route

Reno → Reno

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR11LA265

Nobody was injured.

The failure of a modified engine mount to keep the engine properly aligned, which resulted in partial failure of the rudder support structure due to the deflection of the jet engine exhaust.

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

Read the full NTSB narrative

While being flown on an air race qualification/training flight, the experimental jet’s engine support mount, which had been recently installed to accommodate an increased-thrust engine modification, failed to keep the engine properly aligned. The resultant misalignment resulted in jet blast being directed onto and melting a portion of the rudder support structure. Although there was no indication of the problem in flight, during the landing roll, the pilot discovered that the rudder did not function properly, and directional control had to be maintained by alternate means. During the investigation, it was determined that five other racing airplanes of the same make and model had been modified in a similar manner and that there were slight structural variations and areas of poor welding associated with some of the mounts. As a result of this accident, the manufacturer of the engine modification instituted a program to obtain an independent professional engineering analysis of the engine mount design. Later, in response to another accident, the National Transportation Safety Board (NTSB) issued Safety Recommendation A-12-13, which asked the Reno Air Race Association (RARA) to require aircraft owners to provide an engineering evaluation for aircraft with any major modification. On August 27, 2012, pending receipt of further information showing that the process proposed by RARA specifically requires an owner of an aircraft with a major modification to provide an engineering evaluation that includes flight demonstrations and analysis within the anticipated flight envelope, the NTSB classified the recommendation Open-Acceptable Response.

Quoted verbatim from the NTSB record.