# NTSB ANC09LA088: Cessna 170B, N6073V, Anchorage, AK, August 25, 2009 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: August 25, 2009, 09:56 local (17:56 UTC) - Place: Anchorage, AK - Coordinates: 61.186943, -149.954437 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=61.1869&lon=-149.9544&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed, report June 17, 2010 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: Federal Aviation Administration (Airworthiness) - NTSB case key (mKey): 74595 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC09LA088 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/74595/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=74595 - Page: https://openairdocs.org/ntsb/ANC09LA088 ## Probable cause The pilot’s decision to make an abrupt and steep low altitude turn just after takeoff, while attempting to return to his departure airport, resulting in an aerodynamic stall and loss of aircraft control. Contributing to the accident was the pilot’s failure to ensure that the airplane’s engine access cowling was properly latched before takeoff. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters: airspeed](https://openairdocs.org/ntsb-findings/01062010): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Cessna 170B, 13 cases](https://openairdocs.org/ntsb-findings/01062010/cases.md?model=2072306), [All aircraft, 1,681 cases](https://openairdocs.org/ntsb-findings/01062010/cases.md) - [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Cessna 170B, 15 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md?model=2072306), [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md) - [Doors: service doors](https://openairdocs.org/ntsb-findings/01035240): Aircraft › Aircraft structures · Incorrect use/operation (probable cause); cases with it: [Cessna 170B, 1 case](https://openairdocs.org/ntsb-findings/01035240/cases.md?model=2072306), [All aircraft, 5 cases](https://openairdocs.org/ntsb-findings/01035240/cases.md) - [Action: incomplete action](https://openairdocs.org/ntsb-findings/02041040): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Cessna 170B, 1 case](https://openairdocs.org/ntsb-findings/02041040/cases.md?model=2072306), [All aircraft, 105 cases](https://openairdocs.org/ntsb-findings/02041040/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Initial climb: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) (defining event); cases with it: [Cessna 170B, 3 cases](https://openairdocs.org/ntsb-events/330/sequence.md?model=2072306), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md) - [Initial climb: Loss of control in flight](https://openairdocs.org/ntsb-events/240); cases with it: [Cessna 170B, 19 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=2072306), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Initial climb: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241); cases with it: [Cessna 170B, 9 cases](https://openairdocs.org/ntsb-events/241/sequence.md?model=2072306), [All aircraft, 1,529 cases](https://openairdocs.org/ntsb-events/241/sequence.md) - [Uncontrolled descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Cessna 170B, 52 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=2072306), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The private pilot was departing on a Title 14, CFR Part 91, personal flight. Witnesses reported that shortly after it became airborne, the right engine access cowling opened, and the airplane began a steep left turn back to the airport. As the airplane’s left bank increased, it descended nose first into tundra-covered terrain. The pilot said he could not specifically recall latching the cowling after preflighting the airplane, and that he should have climbed the airplane higher before returning to the airport. Examination of the airplane did not disclose any preimpact mechanical malfunction. Given the lack of mechanical deficiencies with the airplane's engine or flight controls, in conjunction with the witness and the pilot’s statement, it is likely the pilot failed to properly latch the engine access cowling before takeoff, then failed to adequately maintain control of the airplane while returning to the airport after the cowling opened. ## Factual narrative On August 25, 2009, about 0956 Alaska daylight time, a Cessna 170B airplane, N6073V, received substantial damage when it collided with tundra-covered terrain following a loss of control shortly after takeoff from Runway 31 at the Lake Hood Airstrip, Anchorage, Alaska. The airplane was being operated as a visual flight rules (VFR) personal flight under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91, when the accident occurred. The sole occupant, a private pilot, sustained serious injuries. Visual meteorological conditions prevailed, and no flight plan was filed. The flight was en route to the Wasilla Airport, Wasilla, Alaska. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on August 25, a pilot that was preparing to depart behind the accident airplane said that shortly after it became airborne, he saw the right engine access cowling open. In a written statement to the NTSB, the witness reported: “I saw the Cessna 170B climbing out from Runway 31 and at approximately 150 to 200 feet above the runway, the right cowl came loose, and violently flapped and twisted straight up and against the nose of the airplane.” The witness said that as the accident airplane’s climb continued, the wing of his airplane blocked his view, and he lost sight of it just before the accident. Other witnesses from around the Lake Hood Airstrip reported to the NTSB IIC that just after takeoff, the accident airplane’s climb shallowed, then it began a steep left turn back to the airstrip, which was followed by a rapid, nose and left wing low descent. The airplane collided with an area of swampy, tundra-covered terrain about 275-yards northwest of the departure end of Runway 31. The NTSB IIC, and a Federal Aviation Administration (FAA) airworthiness inspector, Anchorage Flight Standards District Office, traveled to the accident site on August 25 to inspect the airplane wreckage before recovery. An examination revealed no mechanical anomalies with the airplane, engine, or the engine cowling latch system. The engine access cowlings are hinged at the top by a piano hinge, which measures about 28 inches long, allowing each cowling to swing upward for inspection of the engine. When the engine access cowlings are closed, each is locked in place by two hook and lever style latches, one forward, and one aft, mounted on the lower portion of each cowling. During a hospital room interview with the NTSB IIC on September 11, the pilot reported that he opened both engine access cowlings as part of his preflight inspection, but he could not specifically recall latching either side once he finished. He added that just after takeoff he saw the right engine access cowling open, and when he started a steep left turn back to the airport, the airplane descended nose down. He said that the next thing he recalls is regaining consciousness as rescue crews began to arrive on scene. Additionally, he stated, in part:“I should have climbed higher before returning to the airport.” The pilot said that other than the open engine access cowling, there were no preimpact mechanical problems with the airplane. Due to the pilot’s extensive injuries sustained in the accident, he was unable to complete an NTSB accident report form. ## Aircraft - Registration: [N6073V](https://openairdocs.org/deregistered/N6073V-2011-05-14), registration cancelled 2011-05-14, S/N 25281, built 1961 (OpenAirDocs) - Reported make and model: CESSNA 170B - Registry model: [Cessna 170B](https://openairdocs.org/model/cessna-170b) (registry code 2072306) (OpenAirDocs) - Registry engine: [Continental C145 series](https://openairdocs.org/engine/continental-c145-series) (registry code 17012, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 25281 - Engines: CONT MOTOR C145 SERIES 145 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Carl W. Fundeen - Registered owner: Carl W. Fundeen - Airworthiness certificate: Standard, Normal - Departed: Z41, Anchorage, AK - Destination: IYS, Wasilla, AK - Airport: Z41, Lake Hood Airstrip, runway 31, 2,200 × 70 ft, gravel ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 67; injuries: serious; private; airplane ratings: single-engine land; medical: class 3, with waivers/limitations; seat: left; flight hours: 675 total, 50 in this make and model, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 360° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: 8,000 ft overcast - Temperature: 52 °F, dew point 45 °F - Altimeter: 29.54 inHg - Observed at: Z41, 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 20090825049299A](https://openairdocs.org/incident/20090825049299A), Aug 25, 2009: Cessna 170B, Anchorage, AK, Substantial damage. Based on witness statements and photographs of the engine cowl, it appears the engine cowling came loose and was flapping upon takeoff. Also based on witness… ## Other investigations on N6073V (1) 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 NYC66F0156](https://openairdocs.org/ntsb/NYC66F0156), Jul 28, 1965: Cessna 170B (N6073V), Middletown, NJ, substantial damage ## Docket (2 files) The files NTSB released with the investigation on April 15, 2010, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=74595. 143 KB in all. - Witness Statements (item 1, .PDF, 70 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40328520&FileExtension=.PDF&FileName=Witness%20Statements-Redacted.PDF - Record of Conversation/Interview (item 2, .PDF, 73 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40328521&FileExtension=.PDF&FileName=Record%20of%20Conversation%2FInterview-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.