# NTSB ANC97FA037: Short Brothers SC7, N451SA, Nunapitchuk, AK, March 25, 1997 - Type: NTSB accident investigation - Classification: Accident · Fatal · Field investigation · Final report - Date: March 25, 1997, 11:23 local (15:23 UTC) - Place: Nunapitchuk, AK - Coordinates: 60.880725, -162.460968 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=60.8807&lon=-162.4610&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: Fatal - Injuries: 2 fatal - Status: Completed, report May 29, 1998 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - NTSB case key (mKey): 2932 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC97FA037 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/2932/pdf - Page: https://openairdocs.org/ntsb/ANC97FA037 ## Probable cause (aircraft 2) inadequate visual look-out by the pilots of both airplanes, which resulted in their failure to see-and-avoid each other's airplanes. ## Probable cause (aircraft 1) inadequate visual look-out by the pilots of both airplanes, which resulted in their failure to see-and-avoid each other's airplanes. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Midair collision, climb - to cruise - visual lookout - inadequate, pilot in command (cause) - visual lookout - inadequate, pilot of other aircraft (cause) - In flight collision with terrain/water, descent - uncontrolled - Midair collision, cruise - visual lookout - inadequate, pilot in command (cause) - visual lookout - inadequate, pilot of other aircraft (cause) - In flight collision with terrain/water, descent - uncontrolled ## Analysis (aircraft 2) The pilot of Cessna 207A, N800GA, was returning to his company base, passing about 2 miles north of a remote airstrip that was along the route of flight. The airstrip did not have any control tower. [Communications around an uncontrolled airport are conducted on a common traffic advisory frequency (CTAF)]. The pilot of a Short SC7, N451SA, announced his departure from the same airstrip on the CTAF, and took off in a northerly direction. He then began a climbing right turn toward the same destination as the Cessna 207A was proceeding. The two airplanes collided in mid-air, about 1.49 nautical miles east-northeast of the airstrip, which was about 18.3 miles west of their destination. They were observed spiraling downward from about 800 ft above the ground. Both airplanes were found lying flat and upright on a frozen lake, entangled together at the accident site. The Cessna's burned wreckage was lying on top of (and positioned toward the aft third of) the burned wreckage of the Short SC7. ## Analysis (aircraft 1) The pilot of Cessna 207A, N800GA, was returning to his company base, passing about 2 miles north of a remote airstrip that was along the route of flight. The airstrip did not have any control tower. [Communications around an uncontrolled airport are conducted on a common traffic advisory frequency (CTAF)]. The pilot of a Short SC7, N451SA, announced his departure from the same airstrip on the CTAF, and took off in a northerly direction. He then began a climbing right turn toward the same destination as the Cessna 207A was proceeding. The two airplanes collided in mid-air, about 1.49 nautical miles east-northeast of the airstrip, which was about 18.3 miles west of their destination. They were observed spiraling downward from about 800 ft above the ground. Both airplanes were found lying flat and upright on a frozen lake, entangled together at the accident site. The Cessna's burned wreckage was lying on top of (and positioned toward the aft third of) the burned wreckage of the Short SC7. ## Factual narrative (aircraft 2) SAME AS NARRATIVE ANC-97-F-A037A ## Factual narrative (aircraft 1) HISTORY OF FLIGHT On March 25, 1997, about 1115 Alaska standard time, a Short SC7 airplane, N451SA, and a Cessna 207A airplane, N800GA, collided in mid-air, about 1.49 nautical miles east-northeast of Nunapitchuk, Alaska. The accident location is about 18.3 miles west of Bethel, Alaska. Both airplanes were being operated as visual flight rules (VFR) cross-country positioning flights to Bethel under Title 14 CFR Part 91 when the accident occurred. N451SA, registered to and operated by Arctic Circle Air Service Inc., Anchorage, Alaska, and N800GA, registered to and operated by Grant Aviation Inc., Anchorage, Alaska, were destroyed by impact and postimpact fire. The pilots of each airplane, the sole occupants of their respective airplanes, received fatal injuries. Visual meteorological conditions prevailed. VFR company flight following procedures were in effect for both flights. N451SA departed the village of Nunapitchuk about 1112 for the flight to Bethel. N800GA departed the village of Scammon Bay, Alaska, about 1000 for Bethel. The operators of each airplane reported their respective flights were returning to Bethel after delivering all of their cargo. A ground witness (a pilot for another operator), reported he landed at Nunapitchuk about 1107, and was taxiing to the airport ramp. N451SA was beginning to taxi away from the ramp for departure. The ground witness heard the pilot of N451SA announce his departure intentions from Nunapitchuk on an aircraft radio. N451SA then departed on runway 36. N451SA did not circle over the airport or return to the vicinity of the airport. About 1 and 1/2 minutes later, the witness' attention was directed toward the northeast by a ground agent. The witness observed N451SA descending toward the ground in a nose low attitude. The airplane was rotating counter-clockwise in a descending spiral about 800 feet above the ground. Several villagers, and the ground witness, responded to the accident scene, and observed the wreckage burning on the surface of a small frozen lake. At the point of rest on the ground, the wreckage of N800GA was located entangled with the wreckage of N451SA. N800GA was positioned toward the aft end of N451SA. The accident occurred during the hours of daylight at latitude 60 degrees, 55.068 minutes north, and longitude 162 degrees, 23.700 minutes west. CREW INFORMATION The pilot of N451SA held an airline transport pilot certificate with an airplane multi-engine land rating. He held commercial pilot privileges with airplane single-engine land and sea ratings. In addition, the pilot held a flight instructor certificate with airplane single-engine, multi-engine, and instrument airplane ratings. The most recent first-class medical certificate was issued to the pilot on February 21, 1997, and contained no limitations. According to the pilot/operator report submitted by the operator, the pilot of N451SA accrued a total aeronautical experience of about 3,170 hours, of which 130 hours were in the accident airplane make and model. In the preceding 90 and 30 days prior to the accident, the report listed a total of 220, and 91 hours, respectively. The pilot of N800GA held a commercial pilot certificate with airplane single-engine land, multi-engine land, and instrument airplane ratings. The pilot also held a flight instructor certificate with airplane singe-engine, multi-engine, and instrument airplane ratings. The most recent first-class medical certificate was issued to the pilot on February 28, 1997, and contained no limitations. According to the pilot/operator report submitted by the operator, the pilot of N800GA had accrued a total aeronautical experience of about 2,437 hours, of which 1,136 hours were in the accident airplane make and model. In the preceding 90 and 30 days prior to the accident, the report listed a total of 125, and 55 hours, respectively. AIRCRAFT INFORMATION N451SA had accumulated a total time in service of 7,473 hours. The airplane is maintained under the manufacturer's inspection program. A 100-hour inspection was completed on March 17, 1997, 23 hours before the accident. The colors of the airplane included blue paint on the upper end of the vertical stabilizers. N800GA had accumulated a total time in service of 10,192.5 hours. The most recent annual inspection was accomplished on April 3, 1996. A 100-hour inspection was completed on February 15, 1997, 61 hours before the accident. The colors of the airplane included white paint on the fuselage and wings, with a maroon or red strip along the side of the airplane. METEOROLOGICAL INFORMATION The closest official weather observation station is Bethel, Alaska, which is located about 18.3 nautical miles east of the accident site. On March 25, 1997, at 1051, an Aviation Routine Weather Report (METAR) was reporting in part: Wind, 012 degrees (magnetic) at 15 knots; visibility, 60 statute miles; sky clear; temperature, 6.1 degrees F; dew point, -6.7 degrees F; altimeter, 29.89 inHg. A ground witness at the Nunapitchuk Airport reported the weather conditions at the time of the accident included clear skies; visibility, about 60 miles; wind, 045 degrees at 15 knots. The position of the sun, in relation to the accident site, was 137.4 degrees (magnetic), at an elevation of 24.4 degrees above the horizon. COMMUNICATIONS The pilot of N451SA announced his departure from Nunapitchuk on the common traffic advisory frequency (CTAF) of 122.9 Hz. The operator's company radio frequency is 123.30 Hz. The pilot of N800GA notified his company's dispatcher of an expected time of arrival (ETA) of 13 minutes on the company radio frequency of 123.12 Hz. The exact time of the call was not noted, but the company dispatcher noted an ETA of 1120 on their flight planning log sheet. Based on an average ground speed for N800GA of 120 knots, the ETA was estimated to have been provided when the airplane was about 26 miles from Bethel. No further communication was received from either pilot. AERODROME AND GROUND FACILITIES The Nunapitchuk Airport has a single gravel runway on a 360/180 degree magnetic orientation. Runway 36 is 2,040 feet long by 60 feet wide. The airport is surrounded by Class E airspace that begins 700 feet above the ground. WRECKAGE AND IMPACT INFORMATION The National Transportation Safety Board investigator-in-charge (IIC) examined the wreckage at the accident site on March 26, 1997. During the on-scene examination of the wreckage, strong winds, exceeding 35 knots, hampered efforts to keep items of wreckage from blowing away. The wreckage of N800GA was located within the wreckage of N451SA. Both airplanes were lying flat, and upright on the surface of a frozen lake. Areas of wind blown snow covered the surface of the lake. No evidence of ground impact gouges, or evidence of a wreckage path, were noted. The surface of the snow exhibited sooting in an area around, and downwind, from the wreckage. N451SA The wreckage of N451SA exhibited extensive fire damage. The nose of N451SA was oriented at the point of rest on a magnetic heading of 303 degrees, (all heading/bearings noted in this report are oriented toward magnetic north). The left wing remained attached to the fuselage, but all of the outer skin was melted. The aileron and flap assemblies remained attached to the airplane. The left engine remained attached to the wing, and was extensively consumed by fire. It was canted about 45 degrees toward the left wing tip. The propeller blades were broken, and the exposed blade ends were melted, about 8 inches outboard from the hub. The right wing remained attached to the fuselage, but was displaced slightly forward from its normal geometry, and oriented with the leading edge canted downward. The inboard end of the wing at the fuselage attach point was fire damaged. The rest of the wing was not damaged by fire, and exhibited s ## Aircraft 1 - Registration: [N451SA](https://openairdocs.org/deregistered/N451SA-1998-08-10), registration cancelled 1998-08-10, S/N SH1972 (OpenAirDocs) - Reported make and model: Short Brothers SC7 - Registry model: [Short Bros. & Harland SC7 SERIES 3](https://openairdocs.org/model/short-bros-harland-sc7-series-3) (registry code 8100512) (OpenAirDocs) - Category: Airplane - Serial number: SH-1972 - Airframe hours: 7473 - Engines: Garrett TPE331-2-201A 675 horsepower turbo prop - Damage: Destroyed - Fire: On-Ground - Flight: Positioning, Part 91 - Operator: Arctic Circle Air Service Inc. - Registered owner: Arctic Air Group - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, March 17, 1997, 23 hours before - Departed: 16A - Destination: BET, BETHEL, AK - Flight plan: Company VFR - Airport: 16A, Nunapitchuk, runway 36, 2,040 × 60 ft, gravel ## Aircraft 2 - Registration: [N800GA](https://openairdocs.org/deregistered/N800GA-1998-07-08), registration cancelled 1998-07-08, S/N 20700495 (OpenAirDocs) - Reported make and model: Cessna 207A - Registry model: [Cessna 207A](https://openairdocs.org/model/cessna-207a) (registry code 2073604) (OpenAirDocs) - Category: Airplane - Serial number: 20700495 - Airframe hours: 10193 - Engines: Continental IO-520-F17B 300 horsepower reciprocating - Damage: Destroyed - Fire: On-Ground - Flight: Positioning, Part 91 - Registered owner: Grant Aviation Inc. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, February 15, 1997, 61 hours before - Departed: SCM, SCAMMON BAY, AK - Destination: BET, BETHEL, AK - Flight plan: Company VFR - Airport: 16A, Nunapitchuk, runway 36, 2,040 × 60 ft, gravel ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot, aircraft N451SA; age 27; flight instructor, airline transport, commercial; airplane ratings: multi-engine land, single-engine sea, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; toxicology performed; flight hours: 3,170 total, 130 in this make and model, 3,070 as pilot in command, 220 in the last 90 days, 91 in the last 30 days, 7 in the last 24 hours - Pilot, aircraft N800GA; age 29; commercial, flight instructor; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; toxicology performed; flight hours: 2,437 total, 1,136 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 12° at 15 knots - Visibility: 60 statute miles - Lowest ceiling: none - Temperature: 7 °F, dew point -0 °F - Altimeter: 29.00 inHg - Observed at: BET, 18 nm away ## FAA reports on this event (2) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 19970325003582A](https://openairdocs.org/incident/19970325003582A), Mar 25, 1997: Stbros SC73, Nunapitchuk, AK, Destroyed, 1 fatal. During climbout was struck from above and behind by N800GA that was overflying 16A and not using CTAF. Both crashed - [Accident 19970325003581A](https://openairdocs.org/incident/19970325003581A), Mar 25, 1997: Cessna 207A, Nunapitchuk, AK, Destroyed, 1 fatal. While over flying 16A collided with N451SA that was climbing out of 16A and not on CTAF. Both fell and burned. 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.