# NTSB ANC05LA088: Aerospatiale ATR-42-300, N42NC, Anchorage, AK, June 16, 2005 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: June 15, 2005, 23:45 local (Jun 16, 2005, 07:45 UTC) - Place: Anchorage, AK - Coordinates: 61.209907, -149.889602 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=61.2099&lon=-149.8896&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed, report March 28, 2006 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: Anchorage FSDO-03 - NTSB case key (mKey): 61770 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC05LA088 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/61770/pdf - Page: https://openairdocs.org/ntsb/ANC05LA088 ## Probable cause A lightning strike during a normal descent for landing, which resulted in structural damage to the airplane's left aileron. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight encounter with weather, descent - normal - weather condition - lightning strike (cause) ## Analysis The Title 14, CFR Part 121 cargo flight was about 32 miles north of the destination airport, descending for landing in instrument meteorological conditions, when it was struck by lightning. The radar and several electrical systems were knocked off-line by the strike. Most of the systems were restored, and the airplane landed without incident. The pilot reported that after takeoff, they deviated around a thunderstorm, and that there were numerous thunderstorms in the area. The pilot said after clearing the thunderstorm, they were flying in clear air. He said along the route, most of the observed thunderstorms were behind them, and that they entered instrument meteorological conditions in a large area of cloud cover. As they started a normal descent for the destination airport in smooth air, he indicated that he and the first officer simultaneously noticed that the radio magnetic indicator needles "spun around in different directions," and that an "instant later" they were struck by lightning. He did not indicate what was observed on the radar screen. The pilot did not report any mechanical anomalies prior to the lightning strike. Portions of the left aileron's lightning strike protection were de-bonded by the strike, and the aileron was replaced. ## Factual narrative On June 15, 2005, about 2345 Alaska daylight time, an Aerospatiale ATR-42-300 airplane, N42NC, sustained substantial damage resulting from a lightning strike during a normal descent, about 32 miles north of Anchorage, Alaska. The airplane was being operated as Flight Yukon 24, by Northern Air Cargo Inc., of Anchorage, as an instrument flight rules (IFR) non-scheduled cargo flight under Title 14, CFR Part 121, when the accident occurred. The two flight crew members and a company maintenance person were not injured. Instrument meteorological conditions prevailed, and an instrument flight plan was filed. The flight originated at Fairbanks International Airport, Fairbanks, Alaska, about 2241. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on June 16, the Director of Safety for the operator said the flight was in meteorological conditions (IMC) and descending normally into the Ted Stevens Anchorage International Airport, Anchorage, when it was struck by lightning. He said the airplane was equipped with functioning radar, which was knocked off-line along with several other electrical systems, but most of the systems were restored in-flight. He said the airplane landed without incident, but sustained structural damage to the left aileron, requiring replacement of the aileron. In a written statement to the NTSB dated June 17, the pilot wrote that after takeoff, they deviated to the southwest around a thunderstorm, and that there were numerous thunderstorms north of the Alaska Range, and in the Fairbanks area. The pilot wrote that after clearing the thunderstorm he was cleared to Talkeetna, Alaska, and that most of the observed thunderstorms were behind them. He stated that after flying through clear air, they entered instrument meteorological conditions, and after receiving clearance from Anchorage Center, started a normal descent for the destination airport in smooth air. He wrote that he and the first officer simultaneously noticed that the radio magnetic indicator needles "spun around in different directions." He did not indicate what was observed on the radar screen. He continued, " an instant later, we were struck by lightning." ## Aircraft - Registration: [N42NC](https://openairdocs.org/deregistered/N42NC-2006-08-22), registration cancelled 2006-08-22, S/N 067, built 1987 (OpenAirDocs) - Reported make and model: Aerospatiale ATR-42-300 - Registry model: [Aerospatiale ALENIA ATR 42-300](https://openairdocs.org/model/aerospatiale-alenia-atr-42-300) (registry code 8680876) (OpenAirDocs) - Registry engine: [Pratt & Whitney Canada PW120](https://openairdocs.org/engine/pratt-whitney-canada-pw120) (registry code 52114, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: 0067 - Airframe hours: 23799 - Engines: Pratt & Whitney Canada PW120 2000 lbs thrust turbo prop - Damage: Substantial damage - Flight: Part 121 - Operator: Northern Air Cargo Inc, doing business as Northern Air Cargo - Registered owner: RNS Leasing, LLC - Airworthiness certificate: Standard, Normal - Last inspection: Continuous airworthiness, February 1, 2005, 874 hours before - Departed: FAI, Fairbanks, AK - Destination: PANC, Anchorage, AK - Flight plan: IFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 39; injuries: none; airline transport, flight engineer; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review May 1, 2005; seat: left; flight hours: 4,549 total, 860 in this make and model, 2,392 as pilot in command, 257 in the last 90 days, 67 in the last 30 days, 6 in the last 24 hours - Co-pilot; age 29; injuries: none; airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations; last flight review May 1, 2005; seat: right; flight hours: 2,166 total, 1,076 in this make and model, 220 as pilot in command, 120 in the last 90 days, 50 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Instrument (IMC), Night/dark - Wind: 0° at 0 knots - Visibility: 0 statute miles - Temperature: 55 °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 20050616011399A](https://openairdocs.org/incident/20050616011399A), Jun 16, 2005: Aerosp ATR42300, Anchorage, AK, Substantial damage. (-23) Lightning strike coming into Anchorage. Knocked out #1 acw, #1 ecu, both reset successfully. Left aileron heavy damage. Replaced aileron. Examined… 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.