# NTSB SEA08LA155: Cessna 172M, N61736, Oakland, CA, June 30, 2008 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: June 30, 2008, 12:50 local (19:50 UTC) - Place: Oakland, CA - Coordinates: 37.721111, -122.220558 - Nearby events: https://openairdocs.org/map.md?lat=37.7211&lon=-122.2206&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: Minor injuries - Injuries: 2 minor - Status: Completed, report August 28, 2008 - Report: Approved by Office Director - Parties: Federal Aviation Administration - NTSB case key (mKey): 68346 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA08LA155 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/68346/pdf - Page: https://openairdocs.org/ntsb/SEA08LA155 ## Probable cause A loss of engine power due to oil starvation. The oil starvation event was due to the failure of maintenance personnel to tighten the mounting bolts for the newly installed vacuum pump. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Vacuum system](https://openairdocs.org/ntsb-findings/01023700): Aircraft › Aircraft systems · Incorrect service/maintenance (probable cause); cases with it: [Cessna 172M, 1 case](https://openairdocs.org/ntsb-findings/01023700/cases.md?model=2072418), [All aircraft, 12 cases](https://openairdocs.org/ntsb-findings/01023700/cases.md) - [Maintenance: installation](https://openairdocs.org/ntsb-findings/02062035): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Cessna 172M, 3 cases](https://openairdocs.org/ntsb-findings/02062035/cases.md?model=2072418), [All aircraft, 371 cases](https://openairdocs.org/ntsb-findings/02062035/cases.md) - [Runway/land/takeoff/taxi surface](https://openairdocs.org/ntsb-findings/03023000): Environmental issues › Physical environment · Not specified; cases with it: [Cessna 172M, 1 case](https://openairdocs.org/ntsb-findings/03023000/cases.md?model=2072418), [All aircraft, 253 cases](https://openairdocs.org/ntsb-findings/03023000/cases.md) - [Fluids: oil](https://openairdocs.org/ntsb-findings/01071020): Aircraft › Fluids/misc hardware · Fluid level (probable cause); cases with it: [Cessna 172M, 3 cases](https://openairdocs.org/ntsb-findings/01071020/cases.md?model=2072418), [All aircraft, 174 cases](https://openairdocs.org/ntsb-findings/01071020/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Cessna 172M, 19 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=2072418), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Cessna 172M, 28 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=2072418), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing-landing roll: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Cessna 172M, 100 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=2072418), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis During cruise flight, the pilot noticed the engine was running rough along with a surge in power. He adjusted the mixture to the full rich position, which seemed to smooth the roughness. A few seconds later, he noticed that the engine oil temperature gauge was rising and he diverted towards a nearby airport. The pilot stated that while en route to the airport, the engine lost power and he initiated a forced landing to an open lot near his position. During the landing roll, the airplane struck a large mound of dirt. Examination of the airplane revealed structural damage to the fuselage. Only residual oil was found in the engine. Examination of the engine revealed evidence of an internal oil starvation induced catastrophic failure. The nuts securing the vacuum pump to the mounting pad were loose. About 10 psi of compressed air was applied to the oil cooler inlet port on the engine. Bubbling oil was observed originating from the vacuum pump mounting pad. No further anomalies were noted. Review of maintenance records revealed that the vacuum pump was replaced prior to the accident flight. ## Factual narrative On June 30, 2008, about 1240 Pacific daylight time, a Cessna 172M, N61736, was substantially damaged during a forced landing near Oakland, California. The commercial pilot and his passenger sustained minor injuries. The airplane was registered to and operated by Flying Vikings Inc. of Hayward, California under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and no flight plan was filed for the local traffic watch flight that originated from the Hayward Executive Airport (HYW), Hayward, California at 1100. According to the pilot, during cruise flight, he noticed the engine was running rough along with a surge in power. The pilot adjusted the mixture to the full rich position, which seemed to smooth the roughness. A few seconds later, the pilot noticed that the engine oil temperature gauge was rising and diverted towards the Oakland International Airport (OAK), Oakland. The pilot stated that while en route to OAK, the engine lost power and he initiated a forced landing into an open lot near his position. During the landing roll, the airplane struck a large mound of dirt and came to rest upright. Examination of the airplane by a Federal Aviation Administration inspector revealed that the right wing and fuselage were structurally damaged. Oil was observed on the undercarriage of the airplane from the engine aft to the empennage. On July 24, 2008, the airframe and engine were examined by the NTSB investigator-in-charge at the facilities of Plane Parts, Pleasant Grove, Sacramento. The Lycoming O-320-E2D engine, serial number RL-40510-27A, remained attached to the airframe via all four engine mounts. All of the accessories and cylinders remained attached to the engine crankcase. All four nuts that secured the vacuum pump to the mount pad were found loose. Oil was observed on the rear accessory housing below the vacuum pump and between the left and right magneto. When removed, the oil dipstick indicated no oil within the oil sump. All open lines were plugged with end caps and about 10 psi of compressed air was applied to the oil cooler inlet line. Bubbling oil was observed originating from the vacuum pump mounting pad. The vacuum pump and both magnetos were removed from the engine. The bottom portion of the vacuum pump seal was saturated with oil. The crankshaft was rotated by hand using the propeller and was noted to be extremely stiff. Thumb compression was obtained on all four cylinders. The oil suction finger screen was removed and exhibited metallic debris inside the screen. The number one and three cylinders were removed and examined. Both cylinders exhibited a normal amount of combustion deposits within the cylinder dome. Both pistons were intact and exhibited scuffing on the piston skirt. All internal connecting rods visually appeared to be intact. The number three and four connecting rods along with the general area of the crankshaft exhibited thermal discoloration. The left magneto producedspark on all leads when the magneto drive shaft was rotated by hand with impulse coupling engagement. The right magneto produced spark on all leads when the magneto drive shaft was rotated using an electric hand drill. The propeller remained attached to the crankshaft propeller flange. One of the two blades was slightly bent aft about 10 degrees and the other propeller blade was undamaged. Review of the engine logbook revealed that the engine underwent its most recent 100-hour/annual inspection on June 16, 2008 at a tachometer time of 3,036.9 hours and 3,910.6 hours since major overhaul. A squawk sheet located within the airplane indicated that the vacuum pump was replaced after the most recent flight recorded prior to the accident flight on July 27, 2008. According to the FAA inspector who responded to the accident site, during a telephone interview, the airframe and power plant rated mechanic who installed the vacuum pump reported that he installed the vacuum pump and tightened all the nuts except for the bottom left, which he could not reach. The mechanic stated that he used a screwdriver and hammer to tighten the nut. ## Aircraft - Registration: [N61736](https://openairdocs.org/deregistered/N61736-2009-04-08), registration cancelled 2009-04-08, S/N 17264762, built 1975 (OpenAirDocs) - Reported make and model: Cessna 172M - Registry model: [Cessna 172M](https://openairdocs.org/model/cessna-172m) (registry code 2072418) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 17264762 - Airframe hours: 13036 - Engines: Lycoming O-320-E2D 150 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial observation, Part 91 - Registered owner: Flying Vikings - Airworthiness certificate: Standard, Normal - Last inspection: Annual, June 1, 2008 - Departed: KHWD, Hayward, CA ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 36; injuries: minor; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review May 1, 2007; seat: left; flight hours: 992 total, 770 in this make and model, 926 as pilot in command, 311 in the last 90 days, 100 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 290° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 66 °F, dew point 55 °F - Altimeter: 30.05 inHg - Observed at: KHWD, 4 nm away ## Other investigations on N61736 (1) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB LAX82FVG02](https://openairdocs.org/ntsb/LAX82FVG02), Oct 24, 1981: Cessna 172 (N61736), Fair Oaks, CA, substantial damage From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.