# NTSB ANC08LA018: Cessna 150, N11764, Palmer, AK, November 9, 2007 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: November 9, 2007, 18:23 local (22:23 UTC) - Place: Palmer, AK - Coordinates: 61.5947222222222, -149.088611111111 - Nearby events: https://openairdocs.org/map.md?lat=61.5947&lon=-149.0886&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Highest injury: Serious injuries - Injuries: 2 serious - Status: Completed, report May 28, 2008 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: Federal Aviation Administration - NTSB case key (mKey): 67081 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC08LA018 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/67081/pdf - Page: https://openairdocs.org/ntsb/ANC08LA018 ## Probable cause The flight instructor's inadequate supervision of the student, and his delayed go-around. Contributing to the accident was dark night conditions. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight collision with object, go-around (vfr) - light condition - dark night (contributing factor) - go-around - delayed, pilot in command(cfi) (cause) - supervision - inadequate, pilot in command(cfi) (cause) - In flight collision with object, go-around (vfr) - object - tree(s) ## Analysis The certificated flight instructor (CFI) was providing flight instruction to a student pilot. While on a northerly approach to the runway, during dark night conditions, the CFI said he inadvertently allowed the student pilot to descend too steeply, and with a high airspeed. His verbal command for the student to stop the excessive descent and slow the airspeed was initially followed, but the student pilot again allowed the airplane to attain a rapid descent rate and high airspeed as the approach continued. The CFI took control of the airplane, added full engine power, and initiated a go-around. During the attempted go-around, the CFI said he encountered severe windshear. He wrote, in part: "I felt the aircraft had gotten into a severe vertical windshear, and no amount of power we had available was stopping the rate of descent, and we hit the ground." The airplane collided with a stand of trees and came to rest inverted, about 300 yards short of the approach end of the runway, sustaining substantial damage to the wings, fuselage, and empennage. At the time of the accident wind conditions were reported to be 350 degrees (true) at 9 knots. An FAA airworthiness inspector reported that during his postaccident inspection of the airplane, no preaccident mechanical anomalies with the airplane were discovered. Due to the absence of any mechanical problems with the airplane, the dark night conditions, and the relatively light winds reported at the time of the accident, it is probable that the accident could have been prevented if the CFI had provided better supervision of the student and initiated a go-around sooner. ## Factual narrative On November 9, 2007, about 1823 Alaska standard time, a Cessna 150 airplane, N11764, sustained substantial damage when it collided with trees and grass-covered terrain while on approach to runway 34, at the Palmer Municipal Airport, Palmer, Alaska. The airplane was being operated by Pegasus Aviation, Palmer, as a visual flight rules (VFR) instructional flight under Title 14, CFR Part 91, when the accident occurred. The certificated flight instructor (CFI) and the student pilot received serious injuries. Dark night visual meteorological conditions prevailed, and no flight plan was filed. The airplane departed the Wolf Lake Airport, Palmer, Alaska, about 1815. A Federal Aviation Administration (FAA) airworthiness inspector from the Anchorage Flight Standards District Office responded to the accident scene shortly after the accident, and examined the airplane prior to recovery efforts. The FAA inspector reported that rescue personnel told him they talked to the student pilot shortly after the accident, and before he was transported to the hospital. They said the student pilot told them that the airplane struck a stand of trees at the approach end of runway 34, while he was receiving dual instruction during dark night conditions. The airplane came to rest inverted, about 300 yards short of the approach end of runway 34. It sustained substantial damage to the wings, fuselage, and empennage. The FAA airworthiness inspector reported that during his postaccident inspection of the airplane, no preaccident mechanical anomalies with the airplane were discovered. The CFI did not complete an NTSB Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1). In a written statement to the FAA, dated January 24, the CFI reported that while on final approach to runway 34, he inadvertently allowed the student pilot to descend too steeply, and with higher than normal airspeed. He said his verbal command for the student to arrest the descent and slow the airplane's airspeed was initially followed, but the student pilot again allowed the airplane to attain a rapid descent rate and high airspeed as the approach continued. The CFI said that he then took control of the airplane, added full engine power, and initiated a go-around. During the attempted go-around, the CFI said he encountered a severe windshear. He wrote, in part: "I felt the aircraft had gotten into a severe vertical wind shear, and no amount of power we had available was stopping the rate of descent, and we hit the ground." The closest weather observation station is the Palmer Municipal Airport. On November 9, at 1753, an Aviation Routine Weather Report (METAR) was reporting in part: Sky conditions and ceiling, 8,500 feet broken; visibility, 10 statute miles; wind, 350 degrees (true) at 9 knots. ## Aircraft - Registration: [N11764](https://openairdocs.org/deregistered/N11764-2017-04-13), registration cancelled 2017-04-13, S/N 15075619, built 1974 (OpenAirDocs) - Reported make and model: Cessna 150 - Registry model: [Cessna 150L](https://openairdocs.org/model/cessna-150l) (registry code 2071826) (OpenAirDocs) - Registry engine: [Continental 0-200 series](https://openairdocs.org/engine/continental-0-200-series) (registry code 17020, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 15075619 - Engines: Continental O-200 100 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: Pegasus Aviation - Registered owner: Michael R. Poston - Airworthiness certificate: Standard, Normal - Departed: 4AK6, Palmer, AK - Destination: PAQ, Palmer, AK - Airport: PAQ, Palmer Muni, runway 34, 6,009 × 100 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 55; injuries: serious; commercial, flight instructor; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; seat: right; flight hours: 2,400 total, 2,000 in this make and model, 40 in the last 90 days, 1 in the last 24 hours - Student pilot; age 49; injuries: serious; student; medical: class 3, with waivers/limitations; seat: left; flight hours: 10 total ## Weather - Conditions: Visual (VMC), Night/dark - Wind: 350° at 9 knots - Visibility: 10 statute miles - Lowest ceiling: 8,500 ft broken - Temperature: 34 °F, dew point 19 °F - Altimeter: 28.87 inHg - Observed at: PAQ, 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 20071109828399A](https://openairdocs.org/incident/20071109828399A), Nov 9, 2007: Cessna 150L, Palmer, AK, Destroyed. (-23) On approach to runway 34 the aircraft contacted numerous tree tops, approximately 300 yards before touch down. The trees form a line approximately 50… ## Other investigations on N11764 (2) 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 ANC78DAG90](https://openairdocs.org/ntsb/ANC78DAG90), Jul 30, 1978: Cessna 150L (N11764), Wasilla, AK, substantial damage - [NTSB ANC77DAG61](https://openairdocs.org/ntsb/ANC77DAG61), Jun 3, 1977: Cessna 150L (N11764), Anchorage, AK, 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.