# NTSB WPR10LA220: Cessna 172N, N733SN, Tamuning, April 30, 2010 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: April 30, 2010, 16:30 UTC - Place: Tamuning - Coordinates: 13.483333, 144.800003 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=13.4833&lon=144.8000&mi=10 - Phase of flight: [Standing](https://openairdocs.org/ntsb-phases/150) (OpenAirDocs' grouping) - Defining event: [Standing-engine(s) not oper: Miscellaneous/other](https://openairdocs.org/ntsb-events/900) - Highest injury: Serious injuries - Injuries: 1 serious, 1 uninjured - Status: Completed, report July 22, 2010 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 75899 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR10LA220 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/75899/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=75899 - Page: https://openairdocs.org/ntsb/WPR10LA220 ## Probable cause The failure of the pilot to maintain clearance with the airplane’s propeller while hand-propping. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Action: incorrect action performance](https://openairdocs.org/ntsb-findings/02041015): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Cessna 172N, 29 cases](https://openairdocs.org/ntsb-findings/02041015/cases.md?model=2072434), [All aircraft, 1,386 cases](https://openairdocs.org/ntsb-findings/02041015/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Standing-engine(s) not oper: Miscellaneous/other](https://openairdocs.org/ntsb-events/900) (defining event); cases with it: [Cessna 172N, 15 cases](https://openairdocs.org/ntsb-events/900/sequence.md?model=2072434), [All aircraft, 1,556 cases](https://openairdocs.org/ntsb-events/900/sequence.md) ## Analysis Unable to get the engine started, the pilot elected to exit the airplane and turn the propeller by hand. The pilot turned off all electrical power and took the keys out of the ignition after turning the magnetos to off prior to exiting the cockpit. As he turned the propeller with both hands his head went beneath the propeller, which struck his head and resulted in a serious injury to the pilot. ## Factual narrative On April 30, 2010, about 1630 local time, a Cessna 172N, N733SN, registered to Micronesian Aviation Systems Inc., and operated by a private pilot, had the propeller strike the pilot while the airplane was being prepared for a 14 Code of Federal Regulations (CFR) Part 91 personal flight. Visual meteorological conditions prevailed, and no flight plan was filed. The private pilot received serious injuries, and the safety pilot in the airplane and occupying the right front seat was not injured. The airplane, which was being prepared to be flown when the accident occurred, was not damaged. In a statement submitted to the Safety Board investigator-in-charge (IIC), the safety pilot reported that during the starting sequence the pilot was unable to start the engine. The safety pilot stated that after attempting two more start attempts the pilot said that he would exit the airplane and rotate the propeller [by hand] to see if that would “help out with the engine start.” The safety pilot further reported that prior to exiting the airplane the pilot pulled the mixture to the cutoff position, pulled the throttle to idle, turned off the master switch, and turned the magnetos off and pulled out the keys. The safety pilot reported that the pilot then exited the airplane and proceeded to the propeller where “…he turned the propeller a few times with one hand, and then with both hands. As he turned the propeller with both hands his head went beneath the propeller and [it] struck his head.” The safety pilot added that emergency medical personnel responded to the injured pilot a short time later and transported him to a local hospital for treatment. ## Aircraft - Registration: [N733SN](https://openairdocs.org/deregistered/N733SN-2025-11-29), registration cancelled 2025-11-29, S/N 17268514, built 1977 (OpenAirDocs) - Reported make and model: CESSNA 172N - Registry model: [Cessna 172N](https://openairdocs.org/model/cessna-172n) (registry code 2072434) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 17268514 - Airframe hours: 9278 - Engines: Lycoming O-320 160 horsepower reciprocating - Damage: No damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal; Standard, Utility - Last inspection: Annual, April 21, 2010, 65 hours before - Departed: GUM, Tamuning - Destination: GUM, Tamuning - Airport: GUM, Guam International Airport ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 44; injuries: serious; private; airplane ratings: single-engine land; medical: class 3, with waivers/limitations; last flight review December 24, 2008; seat: left; flight hours: 233 total - Other flight crew; age 29; injuries: none; flight instructor, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review February 27, 2009; seat: right; flight hours: 1,850 total ## Weather - Conditions: Visual (VMC), Day - Wind: 90° at 12 knots, gusting 18 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 84 °F, dew point 75 °F - Altimeter: 29.86 inHg - Observed at: GUM ## 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 20100430033449A](https://openairdocs.org/incident/20100430033449A), Apr 30, 2010: Cessna 172N, Tamuning, GU, No damage. On APRIL30, 2010 at approximately 1630 local time a private pilot and CFI were preparing for a local instructional flight. After several attempts to engage the… ## Docket (2 files) The files NTSB released with the investigation on June 21, 2010, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=75899. 894 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 781 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40331649&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Safety Pilot Statement (item 2, .PDF, 113 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40331650&FileExtension=.PDF&FileName=Safety%20Pilot%20Statement-Redacted.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.