# NTSB WPR21LA264: Christen Industries A-1, N9609H, Twin Falls, ID, July 1, 2021 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Limited · Final report - Date: June 30, 2021, 20:45 local (Jul 1, 2021, 02:45 UTC) - Place: Twin Falls, ID - Coordinates: 42.39, -114.57 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=42.3900&lon=-114.5700&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Western Pacific Region - Parties: FAA FSDO - SAIBs cited in the narratives: [SAIB CE-09-35](https://openairdocs.org/saib/CE-09-35) (OpenAirDocs) - NTSB case key (mKey): 103444 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR21LA264 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/103444/pdf - Page: https://openairdocs.org/ntsb/WPR21LA264 ## Probable cause Partial loss of engine power during a low pass, due to carburetor icing and the pilot’s failure to use carburetor heat during the landing approach. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Use of equip/info: use of checklist](https://openairdocs.org/ntsb-findings/02063030): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Christen Industries A-1, 1 case](https://openairdocs.org/ntsb-findings/02063030/cases.md?model=221020X), [All aircraft, 336 cases](https://openairdocs.org/ntsb-findings/02063030/cases.md) - [Action: forgotten action/omission](https://openairdocs.org/ntsb-findings/02041035): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Christen Industries A-1, 1 case](https://openairdocs.org/ntsb-findings/02041035/cases.md?model=221020X), [All aircraft, 440 cases](https://openairdocs.org/ntsb-findings/02041035/cases.md) - [Ice/rain protection system: intake anti-ice, deice](https://openairdocs.org/ntsb-findings/01023020): Aircraft › Aircraft systems · Not used/operated (probable cause); cases with it: [Christen Industries A-1, 1 case](https://openairdocs.org/ntsb-findings/01023020/cases.md?model=221020X), [All aircraft, 108 cases](https://openairdocs.org/ntsb-findings/01023020/cases.md) - [Temp/humidity/pressure: conducive to carburetor icing](https://openairdocs.org/ntsb-findings/03031030): Environmental issues › Conditions/weather/phenomena · Effect on equipment (probable cause); cases with it: [Christen Industries A-1, 1 case](https://openairdocs.org/ntsb-findings/03031030/cases.md?model=221020X), [All aircraft, 435 cases](https://openairdocs.org/ntsb-findings/03031030/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-low-alt flying: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Christen Industries A-1, 1 case](https://openairdocs.org/ntsb-events/342/sequence.md?model=221020X), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Landing-landing roll: Nose over/nose down](https://openairdocs.org/ntsb-events/096); cases with it: [Christen Industries A-1, 4 cases](https://openairdocs.org/ntsb-events/096/sequence.md?model=221020X), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md) ## Analysis The pilot reported that he was practicing basic flight maneuvers at an altitude of about 3,500 ft agl during a short uneventful local flight. He then reduced engine power to idle and initiated a descent back to the private dirt airstrip with the intention of first performing a low pass to confirm the runway was clear, and then landing. As he flew past the runway, he applied full throttle, but the engine did not respond. He then performed a forced landing into an adjacent wheat field, where the airplane nosed over during the ground roll. The pilot stated that he had not used a checklist during the descent and forgot to apply carburetor heat. The wing lift struts, and the vertical stabilizer were substantially damaged. The pilot reported that there were no mechanical failures or malfunctions with the airplane or engine that would have precluded normal operation. The carburetor icing chart from FAA Special Airworthiness Information Bulletin CE-09-35 “Carburetor Icing Prevention” indicated a potential for serious icing at glide power for the temperature and dew point depicted at the time of the accident. ## Aircraft - Registration: [N9609H](https://openairdocs.org/aircraft/N9609H), registered now, S/N 1167, built 1990 (OpenAirDocs) - Reported make and model: CHRISTEN INDUSTRIES INC A-1 - Registry model: [Christen Industries A-1](https://openairdocs.org/model/christen-industries-a-1) (registry code 221020X) (OpenAirDocs) - Registry engine: [Lycoming O&VO-360 series](https://openairdocs.org/engine/lycoming-o-vo-360-series) (registry code 41514, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 1167 - Year built: 1990 - Airframe hours: 572.2 - Engines: LYCOMING O-360-C1G 180 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Marc A Williams - Registered owner: Marc A Williams - Airworthiness certificate: Standard, Normal - Last inspection: Annual, November 27, 2020, 27 hours before - Departed: PVT, Hollister, ID - Destination: Same as departure - Airport: PVT, runway 18, 1,500 × 50 ft, grass/turf - Equipment: ADS-B, Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 49; injuries: none; private; airplane ratings: single-engine land; medical: class 3, without waivers/limitations; last flight review May 29, 2020; seat: front; restraint: 5-point; flight hours: 750 total, 145 in this make and model, 675 as pilot in command, 70 in the last 90 days, 16 in the last 30 days, 3.5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Dusk - Wind: 180° at 9 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 79 °F, dew point 46 °F - Altimeter: 29.93 inHg - Observed at: KTWF - METAR: METAR KTWF 010253Z AUTO 18009KT 10SM CLR 26/08 A2993 RMK AO2 SLP074 T02610083 55001= ## 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 20210630012419A](https://openairdocs.org/incident/20210630012419A), Jun 30, 2021: Christen Industries Inc A-1, Hollister, ID, Substantial damage. Pilot took off from a field adjacent to his friends house and climbed to 7500 - 8000 MSL to practice slow flight and steep turns. After 15 minutes he pulled… 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.