# NTSB ANC92FA069: Cessna 172, N73813, Ruth Glacier, AK, May 9, 1992 - Type: NTSB accident investigation - Classification: Accident · No injuries · Field investigation · Final report - Date: May 9, 1992, 10:50 local (18:50 UTC) - Place: Ruth Glacier, AK - Coordinates: 62.449211, -149.790908 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=62.4492&lon=-149.7909&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 10 uninjured - Status: Completed, report September 17, 1993 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - NTSB case key (mKey): 5642 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC92FA069 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/5642/pdf - Page: https://openairdocs.org/ntsb/ANC92FA069 ## Probable cause (aircraft 2) THE FAILURE OF THE PILOTS OF BOTH AIRPLANES TO MAINTAIN AN ADEQUATE VISUAL LOOKOUT. FACTORS WHICH CONTRIBUTED TO THE ACCIDENT WAS THE FAILURE OF THE PILOT OF THE CE-172 TO BECOME AWARE OF AND TO USE THE LISTED FREQUENCY FOR INTER AIRCRAFT COMMUNICATIONS, AND THE REDUCED VISUAL ACUITY OF THE CE-172 AGAINST THE SURROUNDING TERRAIN ## Probable cause (aircraft 1) THE FAILURE OF THE PILOTS OF BOTH AIRPLANES TO MAINTAIN AN ADEQUATE VISUAL LOOKOUT. FACTORS WHICH CONTRIBUTED TO THE ACCIDENT WAS THE FAILURE OF THE PILOT OF THE CE-172 TO BECOME AWARE OF AND TO USE THE LISTED FREQUENCY FOR INTER AIRCRAFT COMMUNICATIONS, AND THE REDUCED VISUAL ACUITY OF THE CE-172 AGAINST THE SURROUNDING TERRAIN. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Midair collision, cruise - normal - visual lookout - inadequate, pilot in command (cause) - visual lookout - inadequate, pilot of other aircraft (cause) - preflight planning/preparation - inadequate, pilot in command (contributing factor) - radio communications - not maintained, pilot in command (contributing factor) - Midair collision, cruise - normal - visual lookout - inadequate, pilot in command (cause) - visual lookout - inadequate, pilot of other aircraft (cause) - preflight planning/preparation - inadequate, pilot of other aircraft (contributing factor) - radio communications - not maintained, pilot of other aircraft (contributing factor) - terrain condition - mountainous/hilly (contributing factor) ## Analysis (aircraft 2) BOTH AIRPLANES WERE ON SIGHTSEEING FLIGHTS AT ABOUT 9,200 FT MSL. THE PILOT OF THE CE-172, N73813, STATED THAT HE WAS HEADING APRX NORTHWEST, LOOKED AT MT. MCKINLEY, AND AS HE RETURNED HIS GAZE FORWARD HE SAW THE OTHER AIRPLANE AHEAD AND SLIGHTLY HIGHER BEFORE THE COLLISION. THE PILOT OF THE CE-185, N1047F, STATED THAT SHE HAD JUST FINISHED MAKING A RADIO TRANSMISSION INDICATING HER POSITION WHEN SOME OF THE PAX SAW THE OTHER AIRPLANE; SHE ESTIMATED THE OTHER AIRPLANE WAS FLYING IN THE OPPOSITE DIRECTION AND SLIGHTLY LOWER. THE ALASKA SUPPLEMENT IN EFFECT AT THE TIME OF THE OCCURRENCE STATED THAT FREQUENCY 122.7 IS DESIGNATED FOR INTER AIRCRAFT COMMUNICATIONS IN DENALI PARK, THE AREA IN WHICH MT. MCKINLEY IS LOCATED. THE PILOT OF THE CE-172 WAS NOT AWARE OF THE FREQUENCY. ACCORDING TO THE PILOT OF THE CE-185, THE CE-172 BLENDED IN WITH THE SURROUNDING TERRAIN WHICH CONSISTED OF VERTICAL GRANITE WALLS. ## Analysis (aircraft 1) BOTH AIRPLANES WERE ON SIGHTSEEING FLIGHTS AT ABOUT 9,200 FT MSL. THE PILOT OF THE CE-172, N73813, STATED THAT HE WAS HEADING APRX NORTHWEST, LOOKED AT MT. MCKINLEY, AND AS HE RETURNED HIS GAZE FORWARD HE SAW THE OTHER AIRPLANE AHEAD AND SLIGHTLY HIGHER BEFORE THE COLLISION. THE PILOT OF THE CE-185, N1047F, STATED THAT SHE HAD JUST FINISHED MAKING A RADIO TRANSMISSION INDICATING HER POSITION WHEN SOME OF THE PAX SAW THE OTHER AIRPLANE; SHE ESTIMATED THE OTHER AIRPLANE WAS FLYING IN THE OPPOSITE DIRECTION AND SLIGHTLY LOWER. THE ALASKA SUPPLEMENT IN EFFECT AT THE TIME OF THE OCCURRENCE STATED THAT FREQUENCY 122.7 IS DESIGNATED FOR INTER AIRCRAFT COMMUNICATIONS IN DENALI PARK, THE AREA IN WHICH MT. MCKINLEY IS LOCATED. THE PILOT OF THE CE-172 WAS NOT AWARE OF THE FREQUENCY. ACCORDING TO THE PILOT OF THE CE-185, THE CE-172 BLENDED IN WITH THE SURROUNDING TERRAIN WHICH CONSISTED OF VERTICAL GRANITE WALLS. ## Aircraft 1 - Registration: [N73813](https://openairdocs.org/aircraft/N73813), registered now, S/N 17267693, built 1976 (OpenAirDocs) - Reported make and model: CESSNA 172 - Registry model: [Cessna 172N](https://openairdocs.org/model/cessna-172n) (registry code 2072434) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 17267693 - Airframe hours: 2584 - Engines: LYCOMING O-360-A4M 180 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Usaf Elmendorf Aero Club - Registered owner: Usaf Elmendorf Aero Club - Airworthiness certificate: Standard, Normal - Last inspection: Annual, December 23, 1991, 96 hours before - Departed: EDF, ELMENDORF AFB, AK - Destination: TKA, TALKEETNA, AK - Flight plan: VFR ## Aircraft 2 - Registration: [N1047F](https://openairdocs.org/aircraft/N1047F), registered now, S/N 18502704 (OpenAirDocs) - Reported make and model: CESSNA 185 - Registry model: [Cessna A185F](https://openairdocs.org/model/cessna-a185f) (registry code 2072821) (OpenAirDocs) - Registry engine: [Continental IO-520 series](https://openairdocs.org/engine/continental-io-520-series) (registry code 17032, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 1852704 - Airframe hours: 5869 - Engines: CONTINENTAL IO-520-D 300 horsepower reciprocating - Damage: Minor damage - Flight: Part 135 - Operator: Douglas Geeting Aviation - Registered owner: Douglas E. Geeting - Airworthiness certificate: Standard, Normal - Last inspection: Annual, March 30, 1992, 80 hours before - Departed: TKA, TALKEETNA, AK - Destination: TKA, TALKEETNA, AK - Flight plan: Company VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot, aircraft N73813; age 26; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 255 total, 88 in this make and model, 254 as pilot in command, 32 in the last 90 days, 12 in the last 30 days - Pilot, aircraft N1047F; age 32; flight instructor, airline transport; airplane ratings: multi-engine land, single-engine sea, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 3,500 total, 700 in this make and model, 3,230 as pilot in command, 15 in the last 90 days, 15 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Visibility: 65 statute miles - Lowest ceiling: none - Temperature: 50 °F - Altimeter: 30.00 inHg ## 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 19920509013992A](https://openairdocs.org/incident/19920509013992A), May 9, 1992: Cessna 172, Ruth Glacier, AK, Substantial damage. Was overtaken and right wing damaged by N1047F that was on converging course. Was unaware traffic radio frequency. - [Accident 19920509013991A](https://openairdocs.org/incident/19920509013991A), May 9, 1992: Cessna A185F, Ruth Glacier, AK, Minor damage. On converging course overtook and struck right wing of N73813. Struck aircraft not on notamed traffic frequency. ## Other investigations on N73813 (1) 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 ANC07CA023](https://openairdocs.org/ntsb/ANC07CA023), Mar 10, 2007: Cessna 172 (N73813), Chugiak, AK, substantial damage. Probable cause: The instructor pilot's inadequate supervision of the student while landing, which resulted in an undershoot, and subsequent in-flight collision with snow-covered terrain. 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.