# NTSB ANC97LA139: Cessna 170B, N4520C, Paxson, AK, September 1, 1997 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: September 1, 1997, 14:45 local (22:45 UTC) - Place: Paxson, AK - Coordinates: 63.700622, -144.890167 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=63.7006&lon=-144.8902&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Highest injury: Serious injuries - Injuries: 2 serious - Status: Completed, report November 10, 1998 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - NTSB case key (mKey): 3060 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC97LA139 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/3060/pdf - Page: https://openairdocs.org/ntsb/ANC97LA139 ## Probable cause The pilot's improper use of carburetor heat during a takeoff in carburetor icing conditions. Factors associated with the accident were the pilot's decision to operate the airplane with known deficiencies (a disabled stall warning horn), an inadvertent stall, and the presence of carburetor icing conditions. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(partial) - nonmechanical, takeoff - initial climb - weather condition - carburetor icing conditions (contributing factor) - carburetor heat - improper use of, pilot in command (cause) - Forced landing, emergency landing after takeoff - Loss of control - in flight, emergency landing after takeoff - stall warning system - disabled (contributing factor) - operation with known deficiencies in equipment - intentional, pilot in command (contributing factor) - stall - inadvertent, pilot in command - In flight collision with terrain/water, descent - uncontrolled ## Analysis The airplane was departing from the 3,500 feet msl airstrip in what the pilot described as 'optimum carb ice conditions' of 40 degrees F with 'lots of moisture.' The carburetor heat control was 'off' for takeoff. At 50 feet above ground level on climb out, the pilot applied carburetor heat and 'the engine died.' She deselected carburetor heat, the engine began to run rough, and the airplane began to lose altitude. When the pilot began a left turn to avoid trees, the left wing and nose dropped, and the airplane impacted terrain. The electric stall warning had been disconnected. ## Factual narrative On September 1, 1997, about 1445 Alaska daylight time, a Cessna 170B airplane, N4520C, sustained substantial damage when it impacted terrain 24 miles to the northeast of Paxson, Alaska. The airplane came to rest 400 feet south of the departure end of a graded, unnamed, airstrip on the middle fork of the Chistochina River, at position 63-07.6 north latitude, 144-38.8 west longitude. The private certificated pilot and single passenger both sustained serious spinal injuries. The airplane was owned and operated by the two occupants. The flight was conducted under 14 CFR Part 91 as a personal flight, returning to Girdwood, Alaska. Visual meteorological conditions prevailed at the time of the accident, and no flight plan was filed. An FAA inspector's examination of the wreckage revealed that the carburetor heat control was in the cold position, and there was fuel in the wing tanks. NTSB interviews with the pilot and passenger revealed that there was a "torrential downpour" of rain the night before the accident, and "lots of dew and moisture" before the takeoff. The pilot also stated that it was "optimum carb icing conditions, and 40 degrees F." The pilot said she did a "longer warmup than normal," and used carburetor heat during back taxi. She said she placed carburetor heat off for the takeoff. She indicated that during the initial climb, passing 50 feet above ground level, she applied carburetor heat and the engine "completely died." She removed the carburetor heat, and the engine came back but, "ran rough, as if it was flooded," and the airplane began to lose altitude. Both occupants described tall trees in the flight path. The pilot described turning left toward lower terrain, the nose and left wing dropping, and impacting in a flat attitude. The pilot said in an interview with the NTSB that the stall warning had been disabled prior to her purchase of the airplane. She stated it was not needed because there is a noticeable buffet prior to the airplane stalling. Type Certificate Data Sheet A-799 states in part, "...the following items of equipment must be installed: ...stall warning kit... ." The Joint Rescue Coordination Center in Anchorage, Alaska, initiated a search after receiving a beacon from the airplane's emergency locator transmitter. The airplane was located about 1700, and the occupants transported to a hospital in Fairbanks, Alaska, at 2000. No NTSB Pilot/Operator Report was received from the pilot. ## Aircraft - Registration: [N4520C](https://openairdocs.org/deregistered/N4520C-2017-04-18), registration cancelled 2017-04-18, S/N 25464, built 1952 (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: 25464 - Airframe hours: 2780 - Engines: Continental C145-2 145 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Erin K. Bashaw - Registered owner: Daniel A. Brokaw - Airworthiness certificate: Standard, Normal - Last inspection: Annual, August 7, 1997, 15 hours before - Destination: AQY, GIRDWOOD, AK - Airport: runway 18, 3,000 × 75 ft, gravel ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 33; private; airplane ratings: single-engine land; medical: class 3, valid medical--no waivers/lim.; seat: left; flight hours: 325 total, 288 in this make and model, 300 as pilot in command, 48 in the last 90 days, 16 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 39 °F ## 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 19970901024809A](https://openairdocs.org/incident/19970901024809A), Sep 1, 1997: Cessna 170B, Paxson, AK, Substantial damage. Aircraft crashed on landing. (.4)the airplane was departing from the 3,500 feet MSL airstrip in what the pilot described as 'optimum carb ice conditions' of 40… 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.