# NTSB WPR16LA101: Antonov AN2, N2AN, San Bernardino, CA, May 6, 2016 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: May 6, 2016, 12:00 local (19:00 UTC) - Place: San Bernardino, CA - Coordinates: 34.114166, -117.215835 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=34.1142&lon=-117.2158&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute: Fuel contamination](https://openairdocs.org/ntsb-events/193) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report May 1, 2017 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: FAA Riverside FSDO, Confederate Air Force - NTSB case key (mKey): 93115 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR16LA101 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/93115/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=93115 - Page: https://openairdocs.org/ntsb/WPR16LA101 ## Probable cause The mechanic’s failure to inspect the fine fuel filter gascolator as required during the most recent inspection, which resulted in a total loss of engine power due to fuel contamination. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Maintenance: scheduled/routine maintenance](https://openairdocs.org/ntsb-findings/02062010): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Antonov AN-2, 1 case](https://openairdocs.org/ntsb-findings/02062010/cases.md?model=056129T), [All aircraft, 320 cases](https://openairdocs.org/ntsb-findings/02062010/cases.md) - [Fuel system: fuel filter-strainer](https://openairdocs.org/ntsb-findings/01022821): Aircraft › Aircraft systems · Not serviced/maintained (probable cause); cases with it: [Antonov AN-2, 1 case](https://openairdocs.org/ntsb-findings/01022821/cases.md?model=056129T), [All aircraft, 52 cases](https://openairdocs.org/ntsb-findings/01022821/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute: Fuel contamination](https://openairdocs.org/ntsb-events/193) (defining event); cases with it: [Antonov AN-2, 1 case](https://openairdocs.org/ntsb-events/193/sequence.md?model=056129T), [All aircraft, 225 cases](https://openairdocs.org/ntsb-events/193/sequence.md) - [Emergency descent: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341); cases with it: [Antonov AN-2, 1 case](https://openairdocs.org/ntsb-events/341/sequence.md?model=056129T), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Emergency descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Antonov AN-2, 1 case](https://openairdocs.org/ntsb-events/470/sequence.md?model=056129T), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The commercial pilot was entering the airport traffic pattern for landing during a familiarization flight. He reported that he turned on the carburetor heat, switched the fuel tank selector to the right fuel tank, and shortly thereafter, the engine experienced a total loss of power. The pilot attempted numerous times to restart the engine but was unsuccessful. After realizing that he would not be able to reach the runway, he decided to make a forced landing to a small field. During the landing approach, the airplane contacted a power line, nosed over, and came to rest inverted, resulting in substantial damage to the wings and fuselage. During the postaccident examination of the airplane, about 16 ounces of water were removed from the fuel system. Water was present in the lower gascolator, the fine fuel filter (upper gascolator), and subsequent fuel line to the carburetor inlet. A brass screen at the carburetor inlet and 2 carburetor fuel bowl thumb screens also contained corrosion, water, and rust. The approved aircraft inspection checklist called for washing the carburetor and main fuel filter every 50 hours and cleaning and/or replacing the fine fuel filter every 100 hours. The fine fuel filter is not easily accessible and not able to be drained during a preflight inspection. The mechanic who completed the most recent inspection stated that he did not drain or check the fine fuel filter. The last logbook entry that specifically stated the fuel filters were cleaned was about 4 years before the accident. ## Factual narrative On May 06, 2016, about 1200 Pacific daylight time, an ANTONOV AN2 airplane, N2AN, sustained substantial damage during a forced landing, following a reported loss of engine power during approach to the San Bernardino International Airport, San Bernardino, California. The airplane was owned by the American Airpower Heritage Flying Museum, and was being operated by the pilot as a familiarization flight under the provisions of 14 Code of Federal Regulations Part 91. The commercial pilot and sole passenger were not injured. Visual meteorological conditions prevailed and no flight plan had been filed for the flight. The airplane departed the Cable Airport, Upland, California, about 1145. In a telephone conversation with the National Transportation Safety Board investigator-in-charge, the pilot stated that the flight was a familiarization flight for a new member of their chapter of the Commemorative Air Force. The flight departed the Cable airport and flew east along the mountains, headed to San Bernardino. They contacted the San Bernardino tower and were instructed to enter the crosswind for runway 24. As part of the before landing checklist, the pilot turned on the carburetor heat and switched the fuel tank selector to the right fuel tank. Shortly thereafter, the engine lost all power. The pilot attempted numerous times to restart the engine, but was unsuccessful. The pilot realized that he would not be able to reach the airport, and decided to make a forced landing to a small field in a residential area. During the landing approach, the airplane contacted a power line. After touching down in the field the airplane nosed over and came to rest inverted, which resulted in substantial damage to the wings and fuselage. During the NTSB examination of the airplane, about 16 ounces of water was removed from the fuel system. Water was present in the lower gascolator, the fine fuel filter (upper gascolator), and subsequent fuel line to the carburetor inlet. A brass screen at the carburetor inlet and 2 carburetor fuel bowl thumb screens also contained corrosion, water and rust. (See Photo 1.) Photo 1 - Fuel and contamination removed from fuel lines and gascolator The approved aircraft inspection checklist called for washing the carburetor and main fuel filter every 50 hours and cleaning and/or replacing the fine fuel filter every 100 hours. The fine fuel filter located halfway up the firewall on the left side of the aircraft is not easily accessible and not in a position to be drained prior to flight. The mechanic that completed the most recent inspection stated that he did not drain or check the fine fuel filter. The last logbook entry that specifically stated the fuel filters were cleaned was in September 2012. ## Aircraft - Registration: [N2AN](https://openairdocs.org/deregistered/N2AN-2018-08-10), registration cancelled 2018-08-10, S/N 43798, built 1984 (OpenAirDocs) - Reported make and model: ANTONOV AN2 - Registry model: [Antonov AN-2](https://openairdocs.org/model/antonov-an-2) (registry code 056129T) (OpenAirDocs) - Registry engine: [Wsk-Pzl-K PZL ASZ-62IR](https://openairdocs.org/engine/wsk-pzl-k-pzl-asz-62ir) (registry code 67203, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 43798 - Year built: 1984 - Airframe hours: 2924 - Engines: PZL ASH 62 IR 1000 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: American Airpower Heritage Flying Museum, doing business as Confederate Air Force - Registered owner: American Airpower Heritage Flying Museum - Airworthiness certificate: Special, Experimental (Special) - Last inspection: AAIP, December 1, 2015, 14 hours before - Departed: CCB, Upland, CA - Destination: SBD, San Bernardino, CA - Equipment: None ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 77; injuries: none; commercial; airplane ratings: single-engine land; medical: class 2, with waivers/limitations; last flight review August 16, 2014; seat: left; restraint: lap only; flight hours: 3,350 total, 58 in this make and model - Pilot-rated passenger; age 44; injuries: none; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 3, without waivers/limitations; last flight review May 4, 2016; seat: right; restraint: lap only; flight hours: 4,000 total, 0 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 320° at 4 knots - Visibility: 7 statute miles - Lowest ceiling: 3,500 ft overcast - Temperature: 63 °F, dew point 48 °F - Altimeter: 29.88 inHg - Observed at: KSBD, 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 20160506008979A](https://openairdocs.org/incident/20160506008979A), May 6, 2016: Antonov AN-2, San Bernardino, CA, Substantial damage. N2AN, AN-2, engine failure while sequencing to land at San Bernardino airport (sbd), hit power lines and flipped while landing in a dirt field. No injuries. ## Docket (6 files) The files NTSB released with the investigation on March 13, 2017, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=93115. 6.3 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 2.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40449873&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Record of Conversation - CAF Mechanic (item 2, .PDF, 29 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40449874&FileExtension=.PDF&FileName=Record%20of%20Conversation%20-%20CAF%20Mechanic-Master.PDF - Materials Laboratory Email Report - Fuel Sample (item 3, .PDF, 41 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40449875&FileExtension=.PDF&FileName=Materials%20Laboratory%20Email%20Report%20-%20Fuel%20Sample-Master.PDF - Statement of Party Representatives to NTSB Investigation (item 4, .PDF, 326 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40449876&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-Master.PDF - Release of Aircraft Wreckage, NTSB Form 6120.15 (item 5, .PDF, 168 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40449877&FileExtension=.PDF&FileName=Release%20of%20Aircraft%20Wreckage,%20NTSB%20Form%206120.15-Master.PDF - Photo Array (item 6, .PDF, 4 photos, 3.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40449878&FileExtension=.PDF&FileName=Photo%20Array-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.