- Date
- July 12, 2023, 16:24 local (Jul 13, 2023, 00:24 UTC)
- Place
- Ninilchik, AK · road
- Injuries
- 1 uninjured
- Damage
- Substantial damage
- Phase of flight
- Enroute
- Aircraft
- N97719Stinson 108
- Defining event
- Enroute: Loss of engine power (total)
- Weather
- Visual (VMC) · Day
- Status
- Completed
- Report
- Approved by Office Director
- Investigation class
- Class 3
- NTSB office
- Alaska Regional Office
- Parties
- FAA/FSDO
- FAA report
- 20230712014659A
- Case key
- 192643
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Probable cause
A partial loss of engine power due to failure of the No. 1 cylinder intake valve head.
Findings · 1
NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.
Sequence of events
The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.
Analysis
The pilot reported that while en route he noticed a loss of engine power and the oil pressure decreasing. He performed a forced landing to a road. During the landing rollout the right wingtip struck a sign, which resulted in substantial damage. Postaccident examination of the engine revealed the No. 1 cylinder was fractured from the engine and remained partially attached by exhaust tubes and the intake manifold. The intake valve stem was fractured about an inch from the interior base of the valve. The piston and intake valve were destroyed by the internal forces in the engine and the fragments were not located.
Factual narrative
On July 12, 2023, about 1624 Alaska daylight time, a Stinson 108 airplane, N97719, was substantially damaged when it was involved in an accident near Ninilchik, Alaska. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot stated he departed Homer Airport (HOM) destined for Anchorage, Alaska. A few miles northwest of the Ninilchik Airport (NIN) he noticed a loss of engine power and the oil pressure decreasing. The pilot determined he was too far from the NIN airport to return so he elected to perform a forced landing to a road. During the landing roll the right wingtip struck a traffic sign, which resulted in substantial damage to the right wing. Postaccident examination of the engine revealed the No. 1 cylinder was fractured from the engine and remained partially attached by exhaust tubes and the intake manifold. The intake valve head and stem was fractured about an inch from the interior base of the valve. The piston and intake valve were destroyed by the internal forces in the engine and the fragments were not located. The pilot reported the engine had a total time of 626 hours at the time of the accident. The last annual inspection was completed 12 months before the accident at an engine total time of 556.4 hours. The engine logbook showed the manufacturer’s recommended time between overhaul is 1,200 hours.
Aircraft
- Registration
- N97719
- Reported as
- Stinson 108
- Category
- Airplane
- Serial number
- 108-719
- Built
- 1946
- Airframe hours
- 3,211
- Engine
- Franklin O335-150-B4, 155 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Personal · Part 91
- Airworthiness certificate
- Standard, Normal
- Last inspection
- Annual · July 30, 2022
- Departed
- PAHO · Homer, AK
- Destination
- PAEN · Kenai, AK
- Airport
- NIN · Ninilchik
- Equipment
- Electronic flight bag or handheld device, Handheld GPS
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 38
- Injuries
- None
- Certificate
- Private
- Airplane ratings
- Single-engine land
- Medical
- Class 3, Without waivers/limitations
- Last flight review
- September 25, 2022
- Seat
- Left
- Restraint
- 4-point
- Flight hours
- 204 total · 130 in this make and model · 149 as pilot in command · 24 in the last 90 days · 10 in the last 30 days
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 180° at 3 knots
- Visibility
- 10 statute miles
- Lowest ceiling
- 1,100 ft broken
- Temperature
- 55 °F, dew point 52 °F
- Altimeter
- 30.16 inHg
- Observed at
- AHO, 24 nm away
- METAR
- PAHO 121953Z 18003KT 10SM SCT007 BKN011 13/11 A3016 RMK AO2 SLP212 T01280106
Docket · 5
The files NTSB released with the investigation on August 21, 2024, on NTSB’s docket system: statements, records, photos and specialists’ reports. 30.6 MB in all.
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.