# NTSB WPR11LA284: Cessna 172S, N222MF, Palo Alto, CA, June 24, 2011 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: June 23, 2011, 20:21 local (Jun 24, 2011, 03:21 UTC) - Place: Palo Alto, CA - Coordinates: 37.461112, -122.114997 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=37.4611&lon=-122.1150&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-landing roll: Nose over/nose down](https://openairdocs.org/ntsb-events/096) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed, report March 20, 2012 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 80880 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR11LA284 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/80880/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=80880 - Page: https://openairdocs.org/ntsb/WPR11LA284 ## Probable cause A total loss of engine power for undetermined reasons during the landing approach over unsuitable terrain. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Cessna 172S, 25 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=2072439), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) - [Terrain: wet/muddy terrain](https://openairdocs.org/ntsb-findings/03021035): Environmental issues › Physical environment · Contributed to outcome; cases with it: [Cessna 172S, 1 case](https://openairdocs.org/ntsb-findings/03021035/cases.md?model=2072439), [All aircraft, 110 cases](https://openairdocs.org/ntsb-findings/03021035/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Approach-VFR pattern base: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341); cases with it: [Cessna 172S, 19 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=2072439), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Approach-VFR pattern base: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Cessna 172S, 15 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=2072439), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing-landing roll: Nose over/nose down](https://openairdocs.org/ntsb-events/096) (defining event); cases with it: [Cessna 172S, 34 cases](https://openairdocs.org/ntsb-events/096/sequence.md?model=2072439), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md) ## Analysis Following an uneventful flight, the pilot entered the airport traffic pattern midfield for his intended runway. While turning from the base leg to the final leg of the pattern, he decided that the airplane was slightly low and advanced the throttle forward; the engine did not respond, and the airplane’s descent rate continued. The pilot then realized that the engine had lost power. He immediately began troubleshooting the loss of engine power and continued toward the runway. Attempts to start the engine were unsuccessful and, realizing that he would not be able to reach the runway, he initiated a forced landing to an open marsh area south of the airport. During the landing roll, the nosewheel dug into the ground and the airplane nosed over. During the postaccident engine examination the engine was run successfully and no mechanical anomalies or failures that would have precluded normal operation were noted; the smell of fuel was present at the accident site. The reason for the loss of engine power was not determined. ## Factual narrative On June 23, 2011, about 2021 Pacific daylight time, a Cessna 172S, N222MF, sustained substantial damage during a forced landing near the Palo Alto Airport (PAO), Palo Alto, California. The airplane was registered to Aviolease LLC, Wilmington, Delaware, and operated by Advanced Flyers, Palo Alto, under the provisions of Title 14 Code of Federal Regulations Part 91. The commercial pilot and his two passengers were not injured. Visual meteorological conditions prevailed and no flight plan was filed for the positioning flight. The cross-country flight originated from Concord, California, at 2000 with an intended destination of PAO. In a written statement, the pilot reported that following an uneventful return flight to PAO, he entered the airport traffic pattern midfield for runway 31. The pilot said that the air traffic control tower (ATCT) controller advised him to follow another aircraft ahead of his position. Upon turning base to final for runway 31, the pilot applied 10 degrees of flaps, and as the airplane descended through about 700 feet above ground level (agl), he determined that the airplane was slightly low. The pilot partially advanced the throttle forward and noted that the airplane's descent rate continued. After the pilot applied full throttle and received no response from the engine, he realized that the engine had lost power. The pilot immediately began troubleshooting the loss of engine power and continued toward the runway, but due to the low sun on the horizon he could not completely see the runway; his attempt to restart the engine was unsuccessful. The pilot initiated a forced landing to an open marsh area south of PAO. During the landing roll, the nose wheel dug into terrain and the airplane nosed over. Examination of the airplane by a Federal Aviation Administration (FAA) inspector revealed that the airplane came to rest within a muddy marsh field about one-half mile south of PAO. The fuselage was bent and buckled aft of the baggage compartment, and the vertical stabilizer and rudder were structurally damaged. The smell of fuel was present at the accident site. The wreckage was recovered approximately three weeks after the accident to a secure location for further examination. According to the FAA inspector, the area where the airplane came to rest was within the tidal area for the marsh land, which resulted in the airplane being partially submerged every few days. Examination of the recovered engine revealed that it remained attached to the airframe via all of its mounts. All engine accessories remained attached to their respective mounts. The top spark plugs were removed from the engine and the engine crankshaft was rotated by hand. Thumb compression was obtained on all four cylinders. The spark plugs were reinstalled along with the ignition harness leads. An external fuel source was attached to the left wing root fuel inlet line in addition to an external power attached to the battery leads. Due to impact damage to thepropeller, a replacement propeller was installed to facilitate the engine run. The engine was started and ran throughout various power settings for about five minutes before being shut down utilizing the mixture control with no anomalies noted. During the engine run, a magneto check was performed and an approximate 100 rpm drop was noted for both the left and right magnetos. In addition, the throttle was advanced momentarily full forward and a peak rpm of about 2600 rpm was observed on the engine tachometer. The reason for the loss of engine power was undetermined. Review of the aircraft maintenance records revealed that the engine was overhauled on March 2, 2007, at an engine and airframe total time of 2,056 hours. The most recent annual inspection was completed on April 1, 2011, at a tachometer time of 1,565 hours. At the time of the accident, the engine had accumulated 1,639.9 hours since major overhaul. ## Aircraft - Registration: [N222MF](https://openairdocs.org/deregistered/N222MF-2018-02-08), registration cancelled 2018-02-08, S/N 172S9391 (OpenAirDocs) - Reported make and model: CESSNA 172S - Registry model: [Cessna 172S](https://openairdocs.org/model/cessna-172s) (registry code 2072439) (OpenAirDocs) - Registry engine: [Lycoming IO-360-L2A](https://openairdocs.org/engine/lycoming-io-360-l2a) (registry code 41597, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 172S9391 - Airframe hours: 3695 - Engines: LYCOMING IO-360-L2A 180 horsepower reciprocating - Damage: Substantial damage - Flight: Positioning, Part 91 - Operator: Advanced Flyers - Registered owner: Aviolease LLC - Last inspection: Annual, April 1, 2011, 42 hours before - Departed: Concord, CA - Destination: PAO, Palo Alto, CA - Airport: PAO, Palo Alto ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 23; injuries: none; commercial; airplane ratings: single-engine land, multi-engine land; medical: class 2, with waivers/limitations; last flight review October 28, 2010; seat: left; flight hours: 308 total, 60 in this make and model, 172 as pilot in command, 3 in the last 90 days ## Weather - Conditions: Visual (VMC), Day - Wind: 130° at 10 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 63 °F, dew point 46 °F - Altimeter: 29.79 inHg - Observed at: PAO, 1 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20110623014229A](https://openairdocs.org/incident/20110623014229A), Jun 23, 2011: Cessna 172S, Palo Alto, CA, Substantial damage. The aircraft was entering the traffic pattern at Palo Alto Airport, Palo Alto, CA. The pilot attempted to add power but the engine was not responding, he… ## Docket (4 files) The files NTSB released with the investigation on October 31, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=80880. 8.4 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 6.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40356342&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Summary of Engine Run Examination (item 2, .PDF, 51 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40356343&FileExtension=.PDF&FileName=Summary%20of%20Engine%20Run%20Examination-Master.PDF - Release of Aircraft Wreckage, NTSB Form 6120.15 (item 3, .PDF, 25 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40356344&FileExtension=.PDF&FileName=Release%20of%20Aircraft%20Wreckage,%20NTSB%20Form%206120.15-Redacted.PDF - Photo 1: View of the recovered wreckage. (item 4, .PDF, 1.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40356345&FileExtension=.PDF&FileName=Photo%201%3A%20View%20of%20the%20recovered%20wreckage.-Master.PDF 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.