# NTSB ANC06LA095: de Havilland DHC-2, N5146G, Big Lake, AK, July 23, 2006 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 23, 2006, 12:15 local (20:15 UTC) - Place: Big Lake, AK - Coordinates: 61.462501, -149.933883 - Nearby events: https://openairdocs.org/map.md?lat=61.4625&lon=-149.9339&mi=10 - Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report February 26, 2007 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: FAA-AL-ANC-FSDO 03 - NTSB case key (mKey): 64184 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC06LA095 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/64184/pdf - Page: https://openairdocs.org/ntsb/ANC06LA095 ## Probable cause The pilot's failure to maintain control of the airplane while step taxiing a float-equipped airplane, which resulted in a collision with an embankment. A factor contributing to the accident was an unfavorable wind. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of control - on ground/water, taxi - directional control - not maintained, pilot in command (cause) - weather condition - unfavorable wind (contributing factor) - On ground/water encounter with terrain/water, taxi - terrain condition - dirt bank/rising embankment ## Analysis The first pilot was conducting a local area Title 14 CFR Part 91 proficiency/instructional flight in a float-equipped airplane with the second pilot. Both pilots were certificated flight instructors. After landing at a lake, the second pilot practiced making step turns. The first pilot, seated in the right seat, then took the flight controls to demonstrate continuous water taxiing/turning while on-step. He said he taxied around the perimeter of the lake and began a right turn, still on-step, but the airplane did not respond. Application of right rudder did not prevent the airplane from colliding with the lake shore and trees. The airplane received damage to the left wing and fuselage. The first pilot indicated that the wind was about 6 knots from the north-northeast, but he thought the airplane encountered a wind shear at the narrowest portion of the lake where the accident occurred. ## Factual narrative On July 23, 2006, about 1215 Alaska daylight time, a float-equipped de Havilland DHC-2 airplane, N5146G, sustained substantial damage when it collided with the shoreline and trees while performing a step turn/taxi on Seven Mile Lake, about 6 miles south-southwest of Big Lake, Alaska. The airplane was being operated as a visual flight rules (VFR) local area proficiency/instructional flight under Title 14, CFR Part 91, when the accident occurred. The airplane was operated by the Civil Air Patrol Inc. (CAP), Anchorage, Alaska. The first pilot, seated in the right seat, and the second pilot, seated in the left seat, both commercial certificated flight instructors, were not injured. Visual meteorological conditions prevailed, and CAP flight following procedures were in effect. The flight originated at the Lake Hood Seaplane Base, Anchorage, about 1015. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on July 23, the flight instructor reported that the flight was intended to familiarize the second pilot with the de Havilland DHC-2 airplane. After landing on the lake, the second pilot practiced making step turns. The first pilot said that he took the flight controls to demonstrate continuous water taxiing/turning while on-step. He said he taxied around the perimeter of the lake and began a right turn, still on-step, but the airplane did not respond. Application of right rudder did not prevent the airplane from colliding with the lake shore and trees. The airplane received damage to the left wing and fuselage. The first pilot indicated that the wind was about 6 knots from the north-northeast, but he thought the airplane encountered a wind shear at the narrowest portion of the lake where the accident occurred. ## Aircraft - Registration: N5146G (not matched to a registry record) - Reported make and model: de Havilland DHC-2 - Category: Airplane - Serial number: 247 - Airframe hours: 11816 - Engines: Pratt & Whitney R-985 450 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Registered owner: Civil Air Patrol Inc. - Airworthiness certificate: Standard, Utility - Last inspection: Annual, June 1, 2006, 12 hours before - Departed: PALH, Anchorage, AK - Flight plan: Company VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 75; injuries: none; commercial, flight instructor; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review May 1, 2006; seat: right; flight hours: 6,008 total, 900 in this make and model, 5,624 as pilot in command, 48 in the last 90 days, 17 in the last 30 days, 4 in the last 24 hours - Other flight crew; age 51; injuries: none; commercial, flight instructor; airplane ratings: multi-engine land, single-engine land, single-engine sea; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review August 1, 2004; seat: left; flight hours: 1,650 total, 50 in this make and model, 8 in the last 90 days, 4 in the last 30 days, 4 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 15° at 6 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 70 °F, dew point 45 °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 20060723014769A](https://openairdocs.org/incident/20060723014769A), Jul 23, 2006: Dhav DHC2MK1, Goose Bay, AK, Substantial damage. (-23) This was a civil air patrol float beaver. The pic/cfi was giving instruction on how to do step turns in a lake. During the demonstration of this maneuver… 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.