# NTSB WPR10LA417: Cessna 172E, N7807U, Mammoth Lakes, CA, August 22, 2010 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: August 22, 2010, 08:33 local (15:33 UTC) - Place: Mammoth Lakes, CA - Coordinates: 37.623889, -118.838607 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=37.6239&lon=-118.8386&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241) - Highest injury: Serious injuries - Injuries: 4 serious - Status: Completed, report January 17, 2012 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: FAA FSDO - NTSB case key (mKey): 77031 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR10LA417 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/77031/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=77031 - Page: https://openairdocs.org/ntsb/WPR10LA417 ## Probable cause The pilot’s failure to maintain adequate airspeed and airplane control during takeoff in high density altitude conditions, which resulted in an aerodynamic stall. ## 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 172E, 2 cases](https://openairdocs.org/ntsb-findings/01062010/cases.md?model=2072412), [All aircraft, 1,681 cases](https://openairdocs.org/ntsb-findings/01062010/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Cessna 172E, 8 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=2072412), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Temp/humidity/pressure: high density altitude](https://openairdocs.org/ntsb-findings/03031020): Environmental issues › Conditions/weather/phenomena · Effect on equipment; cases with it: [Cessna 172E, 3 cases](https://openairdocs.org/ntsb-findings/03031020/cases.md?model=2072412), [All aircraft, 278 cases](https://openairdocs.org/ntsb-findings/03031020/cases.md) - [Terrain: high elevation](https://openairdocs.org/ntsb-findings/03021025): Environmental issues › Physical environment · Effect on operation; cases with it: [Cessna 172E, 1 case](https://openairdocs.org/ntsb-findings/03021025/cases.md?model=2072412), [All aircraft, 16 cases](https://openairdocs.org/ntsb-findings/03021025/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Takeoff: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241) (defining event); cases with it: [Cessna 172E, 1 case](https://openairdocs.org/ntsb-events/241/sequence.md?model=2072412), [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 172E, 12 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=2072412), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot reported that, shortly after takeoff, the airplane encountered turbulence and a downdraft and began to rapidly lose altitude. The pilot was unable to maintain control, and the airplane subsequently collided with the terrain in a nose-low attitude. According to the front-seat passenger, the takeoff roll was long, and the airplane gradually climbed with the stall warning indicator buzzing. He stated that the airplane encountered an updraft followed by a downdraft, the pilot initiated a turn to the left, and the airplane subsequently stalled. The calculated density altitude at the airport at the time of the accident was about 8,900 feet. A postaccident examination of the airframe and engine did not reveal any anomalies that would have precluded normal operation. ## Factual narrative On August 22, 2010, about 0833 Pacific daylight time, a Cessna 172E airplane, N7807U, sustained substantial damage following an in-flight collision with terrain at the Mammoth Yosemite Airport, Mammoth Lakes, California. The private pilot and three adult passengers sustained serious injuries. The airplane sustained structural damage to the forward fuselage and wings. The airplane was being operated by the pilot as a personal cross-country flight under the provisions of 14 Code of Federal Regulations (CFR) Part 91, when the accident occurred. Visual meteorological conditions prevailed, and no flight plan was filed. The flight originated from Mammoth Lakes. In a written statement to the National Transportation Safety Board (NTSB), the pilot reported that shortly after takeoff the airplane encountered turbulence and a downdraft, and began to lose altitude rapidly. The pilot stated he tried to control the airplane; however, it impacted terrain in a nose-low attitude. During a telephone conversation with the NTSB investigator-in-charge, the front seat passenger stated that the takeoff roll was long and they "had a little time taking off, gradually going up with the buzzer going off." He reported that shortly after liftoff, the airplane encountered an updraft followed by a downdraft. He stated the pilot initiated a turn to the left which was followed by a "stall." The four-seat, high-wing, fixed-gear airplane was manufactured in 1964, and powered by a Continental O-300, 145-hp engine. The airplane was equipped with a fixed-pitch propeller. The published maximum gross takeoff weight for the airplane was 2,300 pounds. The pilot did not report the actual takeoff weight of the airplane. A review of recorded weather data from the automated weather observation station at the airport revealed at 0829 conditions in part were: wind from 220 degrees at 5 knots, visibility of 10 statute miles, temperature 18 degrees Celsius, and altimeter 30.18 inches of mercury. The airport elevation was 7,135 feet. Using the reported temperature and altimeter setting, the calculated density altitude during the time of the accident was approximately 8,900 feet. A post impact examination of the airframe and engine did not reveal any anomalies with the airframe or engine that would have precluded normal operation. ## Aircraft - Registration: [N7807U](https://openairdocs.org/deregistered/N7807U-2012-07-26), registration cancelled 2012-07-26, S/N 17251807, built 1964 (OpenAirDocs) - Reported make and model: CESSNA 172E - Registry model: [Cessna 172E](https://openairdocs.org/model/cessna-172e) (registry code 2072412) (OpenAirDocs) - Registry engine: [Continental 0-300 series](https://openairdocs.org/engine/continental-0-300-series) (registry code 17022, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 17251807 - Airframe hours: 3310 - Engines: CONT MOTOR O-300 SER 145 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Tharp, David - Registered owner: Tharp, Bobby - Airworthiness certificate: Standard, Normal - Last inspection: Annual, July 6, 2010 - Departed: KMMH, Mammoth Lakes, CA - Destination: KMMH, Mammoth Lakes, CA - Flight plan: Unknown - Airport: KMMH, Mammoth Yosemite Airport, runway 27, 7,000 × 100 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 48; injuries: serious; private; airplane ratings: single-engine land; medical: class 3, without waivers/limitations; last flight review September 9, 2009; seat: left; flight hours: 1,017 total, 200 in this make and model, 988 as pilot in command, 20 in the last 90 days, 10 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 205° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 64 °F, dew point 32 °F - Altimeter: 30.18 inHg - Observed at: KMMH, 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 20100822044359A](https://openairdocs.org/incident/20100822044359A), Aug 22, 2010: Cessna 172E, Mammoth Lakes, CA, Substantial damage. Pilot departed runway 27 at kmmh ( Mammoth Lakes, CA) at approximately 0820L when the density altitude was 9000 MSL (temp 19 degrees c, airport elevation -… ## Other investigations on N7807U (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 LAX70DUA09](https://openairdocs.org/ntsb/LAX70DUA09), Jan 31, 1970: Cessna 172 (N7807U), Santa Ana, CA, substantial damage ## Docket (4 files) The files NTSB released with the investigation on November 28, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=77031. 1.9 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 260 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40357474&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Record of Conversation (item 2, .PDF, 39 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40357581&FileExtension=.PDF&FileName=Record%20of%20Conversation-Master.PDF - Statement of Party Representatives to NTSB Investigation (item 3, .PDF, 1.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40357501&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-Redacted.PDF - Release of Aircraft Wreckage, NTSB Form 6120.15 (item 4, .PDF, 54 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40371077&FileExtension=.PDF&FileName=Release%20of%20Aircraft%20Wreckage,%20NTSB%20Form%206120.15-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.