Cirrus SR22 N254SR

Summary

On 15 July 2007 at about 23:17 local time, a Cirrus SR22 registered N254SR was involved in an incident near Reno, Nevada, United States. 2 people were on board and nobody was injured. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

15 July 2007 at 23:17

Classification

Incident

Location

Reno, Nevada, United States

Nearest airport

Reno/Tahoe International (RNO)

Coordinates

39.4992, -119.7681

Aircraft

Cirrus SR22

Registration

N254SR

Category

Airplane

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Concord → Reno

Aircraft damage

Not recorded

Weather

VMC

Light

Day

NTSB number

SEA07IA201

Nobody was injured.

The failure of the left turbocharger as a result of a production defect in the unit's compressor due to a machining process change by the manufacturer that was made without formal documentation or substantiation.

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

Read the full NTSB narrative

During cruise flight at 17,000 feet mean sea level, the left turbocharger failed, resulting in a partial engine power loss. The pilot declared an emergency and executed an uneventful landing at an alternate airport. Examination of the turbocharger revealed the turbine wheel was separated from the shaft. Three prior incidents involving similar failures of this part number turbocharger had occurred in May 2007. Examination of the failed turbochargers from all four incidents revealed that all of the units displayed the same discrepancy: the compressor wheel backface perpendicularity to the bore exceeded the maximum permissible value. The source of the perpendicularity error was traced to a change, made in March 2007, to the machining process for the compressor wheel. The change involved a switch from a two-machine process to a three-machine process. This production change was made without formal documentation or coordination with other functional areas; no formal first-article inspection for the new process was performed. In April 2007, the machine shop returned to the original two-machine process. The compressor wheels manufactured during the time that the three-machine process was in use were installed in turbochargers produced from March 20 to April 20, 2007, including the four turbochargers involved in the subject incident and the three May 2007 incidents. The manufacturer issued service bulletins in July 2007 identifying the affected turbochargers by serial number and mandating their replacement. In August 2007, the Federal Aviation Administration issued an airworthiness directive requiring compliance with the service bulletins.

Quoted verbatim from the NTSB record.