WPR09LA145 · Cessna 172R
Cessna 172R · Accident: powerplant system/component malfunction/failure en route
From John Wayne Orange County International Airport (SNA) to Montgomery-Gibbs Executive Airport (MYF)
Event
- NTSB case
- WPR09LA145
- 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
- Accident
- 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
Cessna 172R
- Aircraft type
- Cessna 172
- 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
- N2478B
- Operator
- Alan Jacobson
- Onboard fatalities
- Unknown
- Route
- From John Wayne Orange County International Airport (SNA), Santa Ana, CATo Montgomery-Gibbs Executive Airport (MYF), San Diego, CA
- 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
- Defining eventThe 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
- Powerplant system/component malfunction/failure
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Aircraft › Aircraft power plant
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot made an off-airport forced landing following an in-flight loss of engine power. The No. 4 cylinder (left rear) fractured and separated circumferentially in the area where the head joins the barrel. Metallurgical examination identified a fatigue fracture primarily on the exhaust side of the cylinder head, perpendicular to the axis of the barrel. Its inner edge abutted the crest of the first thread on the barrel. Engine Components, Inc. (ECi), manufactured the cylinder. ECi issued Mandatory Service Bulletin (MSB) No.08-1, Revision 3, dated August 19, 2008. It stated that the purpose of the MSB was to alert their customers about possible fatigue cracking and head separations on a specified group of replacement cylinders for Lycoming parallel valve engines. Cylinders identified by specific serial number ranges were to be inspected and pressure tested or inspected and replaced at specified reduced life limits. On October 20, 2008, Federal Aviation Administration (FAA) Airworthiness Directive (AD) 2008-19-05 became effective and mirrored ECi's MSB serial number range and corrective actions. The AD stated that the intent was to prevent loss of engine power due to cracks at the head-to-barrel interface in the cylinder assemblies and possible engine failure caused by separation of a cylinder head. The cylinders from the accident airplane had serial numbers that were outside of the range listed in the MSB and AD. The FAA has issued a Notice of Proposed Rule Making (NPRM) that would revise the serial numbers covered by the AD to encompass an expanded population of affected cylinders. ECi has a design change that is pending FAA approval.
Probable cause
A total loss of engine power in flight due to the fatigue failure of the No. 4 cylinder.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR09LA145
- Event ID
- 20090308X12520
- Case number
- WPR09LA145
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
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: local date, investigation status. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 2009-03-08.
- API snapshot SHA-256: 1db4a8d0a712b1c3ab0a7db22166e0977e4508c888bf0ab6a3b0555da4a89bc5; retrieved 2026-09-15T10:48:52.684Z.