# NTSB ANC97LA100: Piper PA-18-160, N3952Z, Cantwell, AK, July 8, 1997 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: July 8, 1997, 13:30 local (21:30 UTC) - Place: Cantwell, AK - Coordinates: 63.010387, -149.400802 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=63.0104&lon=-149.4008&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 2 minor - Status: Completed, report November 10, 1998 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - NTSB case key (mKey): 3023 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC97LA100 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/3023/pdf - Page: https://openairdocs.org/ntsb/ANC97LA100 ## Probable cause The pilot's failure to maintain sufficient altitude to clear terrain. Factors were exceeding the airplane's maximum allowable gross weight, and downdrafts and turbulence associated with wind flowing across a mountain ridge. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight encounter with weather, climb - to cruise - weather condition - turbulence,terrain induced (contributing factor) - weather condition - downdraft (contributing factor) - In flight collision with terrain/water, maneuvering - turn to reverse direction - terrain condition - blind/box canyon - altitude/clearance - not maintained, pilot in command (cause) - aircraft weight and balance - exceeded, pilot in command (contributing factor) ## Analysis The air taxi pilot and passenger were approaching a mountain ridge from below. Both occupants described conditions favoring a downslope wind and turbulence at the ridge. The pilot attempted to turn when he realized they would not clear the ridge, but the airplane descended and impacted terrain. The airplane was estimated to weigh 1,827 pounds at the time of the last takeoff. The maximum takeoff weight is 1,760 pounds. The elevation at the accident site was 4,500 feet msl. ## Factual narrative On July 8, 1997, about 1330 Alaska daylight time, a Piper PA-18-160 airplane, N3952Z, sustained substantial damage when it struck a ridge about 15 nautical miles southeast of Cantwell, Alaska, at position 63-13.89 north latitude, 148-34.88 west longitude. The commercial certificated pilot and single passenger sustained minor injuries. The airplane was operated by Ray H. Atkins of Cantwell, Alaska, doing business as Ray Atkins, Registered Guide. The flight was conducted under 14 CFR Part 135 in visual meteorological conditions. The passenger stated to a Federal Aviation Administration inspector during an interview, that the flight was a return leg to Cantwell from Soule lake, and the route of flight was chosen to view mountainous terrain and wildlife. The airplane was flown into a canyon, and while attempting to climb over a ridge, struck terrain. The passenger stated to the NTSB investigator that the airplane was paralleling a ridge on the right side, and climbing to cross a ridge which was ahead of them. When it appeared that the airplane would not clear the ridge, the pilot turned the airplane left and attempted to accelerate. The occupants said it felt as if the plane fell, and then struck the ground hard. It rolled down the mountainside, coming to rest at 4,500 feet msl. The passenger stated that while awaiting rescue, the pilot said several times, " I should have been higher. I was too low. I turned and the downdraft got us." The pilot wrote in his pilot/operator report that the airplane was climbing at 70 miles per hour, along the right side of a valley. He was heading northeast, and attempting to clear a ridge. He stated that he turned the airplane to the left, away from the ridge. The airspeed dropped to zero, he applied power, and lowered the airplane's nose to gain airspeed. The pilot said the left float caught the ground and pulled the left wing into the hillside. The pilot estimated prevailing winds were from the northeast at thirty miles per hour. The passenger said that the winds at the crash site were light from the northeast. This location was at a lower elevation, and downwind of the pass which they had been attempting to clear. The injured pilot was extracted from the wreckage by the passenger. He directed the passenger to turn off the airplane electrical master switch, and activate the Emergency Locator Transmitter. The survivors were located at 1600. At 1730 a helicopter attempted to land but was unable due to the steep terrain. At 2000 the survivors were recovered via hoist by an Alaska Air National Guard helicopter and transported to Anchorage. The empty weight of the airplane is 1,261 pounds according to the loading schedule provided by the pilot. The pilot estimated the fuel on board at the last takeoff to be eighteen gallons of 100 low lead aviation gasoline. His FAA medical certificate dated June 6, 1997, states the pilot weighed 215 pounds. The passenger estimates his weight to be 220 pounds. Baggage estimated by the pilot and passenger was seven pounds. Eight quarts of oil are estimated to be 16 pounds. The estimated total weight at the time of the last takeoff is 1,827 pounds. The maximum allowable takeoff weight is 1,760 pounds. ## Aircraft - Registration: [N3952Z](https://openairdocs.org/aircraft/N3952Z), registered now, S/N 18-7810, built 1962 (OpenAirDocs) - Reported make and model: Piper PA-18-160 - Registry model: [Piper PA-18-150](https://openairdocs.org/model/piper-pa-18-150) (registry code 7101828) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 18-7810 - Airframe hours: 5652 - Engines: Lycoming O-320-A2B 160 horsepower reciprocating - Damage: Substantial damage - Flight: Part 135 - Registered owner: Ray H. Atkins - Airworthiness certificate: Standard, Normal - Last inspection: Annual, April 22, 1997, 25 hours before - Departed: SOULE LAKE, AK - Destination: PATW, GAS LAKE, AK - Flight plan: Company VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 53; commercial; airplane ratings: single-engine land, single-engine sea; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: front; flight hours: 14,800 total, 6,100 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 180° at 6 knots - Visibility: 15 statute miles - Lowest ceiling: 20,000 ft overcast - Temperature: 61 °F, dew point 48 °F - Altimeter: 29.00 inHg - Observed at: PAT, 15 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 19970708017179A](https://openairdocs.org/incident/19970708017179A), Jul 8, 1997: Piper PA18150, Cantwell, AK, Substantial damage. (.4)The air taxi pilot and passenger were approaching a mountain ridge from below. Both occupants described conditions favoring a downslope wind and turbulence… ## Other investigations on N3952Z (4) 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 ANC85LA001](https://openairdocs.org/ntsb/ANC85LA001), Oct 2, 1984: Piper PA-18 (N3952Z), Ohio Creek, AK, substantial damage - [NTSB ANC75DAG79](https://openairdocs.org/ntsb/ANC75DAG79), Mar 25, 1975: Piper PA-18 (N3952Z), Cantwell, AK, substantial damage - [NTSB SEA67D0144](https://openairdocs.org/ntsb/SEA67D0144), Sep 16, 1966: Piper PA-18 (N3952Z), Dillon, MT, substantial damage - [NTSB UNK64X0456](https://openairdocs.org/ntsb/UNK64X0456), Feb 4, 1964: Piper PA18 (N3952Z), Columbus, NE, 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.