SEA07IA201 · Cirrus Design Corp. SR22
Cirrus Design Corp. SR22 · Incident: partial loss of engine power (mechanical failure) en route
From Buchanan Field (CCR) to Reno Tahoe International Airport (RNO)
Event
- NTSB case
- SEA07IA201
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Incident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Cirrus Design Corp. SR22
- Aircraft type
- Cirrus SR22
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N254SR
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Buchanan Field (CCR), Concord, CATo Reno Tahoe International Airport (RNO), Reno, NV
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- En route · cruise
- First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Partial loss of engine power (mechanical failure)
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- None
Cause areas
- Exhaust system, turbocharger › Failure, total
- Manufacturer › Acft/equip, inadequate design
- Manufacturer › Inadequate substantiation process, insuff review
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
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.
Probable cause
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.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record SEA07IA201
- Event ID
- 20070723X00981
- Case number
- SEA07IA201
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status, coordinates, damage. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 38c6be564cb571a14ed9428183fc24948b35f38ad8a4b9d187b38af79df15ba2; retrieved 2026-09-22T03:39:13.048Z.