# NTSB ATL91LA175: Cessna 172K, N78239, Greeneville, TN, September 15, 1991 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: September 14, 1991, 20:30 local (Sep 15, 1991, 00:30 UTC) - Place: Greeneville, TN - Coordinates: 36.07024, -82.860313 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=36.0702&lon=-82.8603&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 6 uninjured - Status: Completed, report March 31, 1993 - Report: Approved by Office Director - NTSB case key (mKey): 8472 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL91LA175 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/8472/pdf - Page: https://openairdocs.org/ntsb/ATL91LA175 ## Probable cause (aircraft 2) THE INADEQUATE VISUAL LOOKOUT BY THE PILOT OF N78239, AND HIS FAILURE TO ACCURATELY JUDGE THE DISTANCE BETWEEN THE TWO AIRCRAFT. FACTORS IN THE ACCIDENT WERE THE DARK NIGHT CONDITIONS AND THE RESULTING VISUAL PERCEPTION OF AIRCRAFT LIGHTING IN DARK CONDITIONS. ## Probable cause (aircraft 1) THE INADEQUATE VISUAL LOOKOUT BY THE PILOT OF N78239, AND HIS FAILURE TO ACCURATELY JUDGE THE DISTANCE BETWEEN THE TWO AIRCRAFT. FACTORS IN THE ACCIDENT WERE THE DARK NIGHT CONDITIONS AND THE RESULTING VISUAL PERCEPTION OF AIRCRAFT LIGHTING IN DARK CONDITIONS. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Midair collision, cruise - normal - light condition - dark night (contributing factor) - visual lookout - inadequate, pilot in command (cause) - distance - misjudged, pilot in command (cause) - visual/aural perception, pilot in command (contributing factor) - Midair collision, cruise - normal - light condition - dark night (contributing factor) - visual lookout - inadequate, pilot of other aircraft (cause) - distance - misjudged, pilot of other aircraft (cause) - visual/aural perception, pilot of other aircraft (contributing factor) - Loss of control - on ground/water, landing - roll - On ground/water collision with object, landing - roll - object - aircraft parked/standing ## Analysis (aircraft 2) BOTH PILOTS HAD PLANNED LOCAL SIGHTSEEING NIGHT FLIGHTS. BOTH AIRCRAFT WERE ON AN EASTERLY HEADING, WITH N78239 (A C172K) IN FRONT OF N73L (A C172D). THE AIRCRAFT WERE IN RADIO CONTACT WITH EACH OTHER AND ATC WAS NOT INVOLVED. N78239 INITIATED A 360-DEGREE TURN, AND VISUALLY ACQUIRED THE LIGHTS OF N73L AFTER RESUMING AN EASTERLY HEADING. THE PILOT OF N78239 STATED THAT 'SUDDENLY WE HIT!' ALTHOUGH AT THE TIME HE THOUGHT THE SPACING BETWEEN AIRCRAFT WAS ABOUT 2 MILES. N78239 LANDED WITHOUT FURTHER INCIDENT DESPITE FLIGHT CONTROL PROBLEMS. N73L LOST DIRECTIONAL CONTROL UPON LANDING AND COLLIDED WITH A PARKED AIRPLANE. INSPECTION OF BOTH AIRCRAFT REVEALED THAT N78239 STRUCK N73L FROM THE REAR, THE RIGHT WING LEADING EDGE OF N78239 CONTACTING THE LEFT MAIN LANDING GEAR OF N73L. THE IMPACT BROKE THE WING SPAR OF N78239 AND SEPARATED THE LEFT MAIN GEAR FROM N73L. ## Analysis (aircraft 1) BOTH PILOTS HAD PLANNED LOCAL SIGHTSEEING NIGHT FLIGHTS. BOTH AIRCRAFT WERE ON AN EASTERLY HEADING, WITH N78239 (A C172K) IN FRONT OF N73L (A C172D). THE AIRCRAFT WERE IN RADIO CONTACT WITH EACH OTHER AND ATC WAS NOT INVOLVED. N78239 INITIATED A 360-DEGREE TURN, AND VISUALLY ACQUIRED THE LIGHTS OF N73L AFTER RESUMING AN EASTERLY HEADING. THE PILOT OF N78239 STATED THAT 'SUDDENLY WE HIT'! ALTHOUGH AT THE TIME HE THOUGHT THE SPACING BETWEEN AIRCRAFT WAS ABOUT 2 MILES. N78239 LANDED WITHOUT FURTHER INCIDENT DESPITE FLIGHT CONTROL PROBLEMS. N73L LOST DIRECTIONAL CONTROL UPON LANDING AND COLLIDED WITH A PARKED AIRPLANE. INSPECTION OF BOTH AIRCRAFT REVEALED THAT N78239 STRUCK N73L FROM THE REAR, THE RIGHT WING LEADING EDGE OF N78239 CONTACTING THE LEFT MAIN LANDING GEAR OF N73L. THE IMPACT BROKE THE WING SPAR OF N78239 AND SEPARATED THE LEFT MAIN GEAR FROM N73L. ## Aircraft 1 - Registration: [N78239](https://openairdocs.org/aircraft/N78239), registered now, S/N 17257540, built 1968 (OpenAirDocs) - Reported make and model: CESSNA 172K - Registry model: [Cessna 172K](https://openairdocs.org/model/cessna-172k) (registry code 2072430) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 17257540 - Engines: LYCOMING O-320-E2D 150 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Broyles, William T - Registered owner: Broyles, William T ## Aircraft 2 - Registration: [N73L](https://openairdocs.org/aircraft/N73L), registered now, S/N 17250283, built 1963 (OpenAirDocs) - Reported make and model: CESSNA 172D - Registry model: [Cessna 172D](https://openairdocs.org/model/cessna-172d) (registry code 2072410) (OpenAirDocs) - Registry engine: [Continental 0-300 series](https://openairdocs.org/engine/continental-0-300-series) (registry code 17022, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 17250283 - Engines: CONTINENTAL O-300-D 145 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Gregory, James K. - Registered owner: Gregory, James K. ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot, aircraft N78239; age 70; private; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; flight hours: 2,200 total, 125 in this make and model, 2,200 as pilot in command, 38 in the last 90 days, 18 in the last 30 days, 4 in the last 24 hours - Pilot, aircraft N73L; age 39; private; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; flight hours: 220 total, 92 in this make and model, 192 as pilot in command, 35 in the last 90 days, 5 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Night/dark - Wind: 60° at 3 knots - Visibility: 5 statute miles - Lowest ceiling: none - Temperature: 81 °F, dew point 73 °F - Altimeter: 30.00 inHg - Observed at: TYS, 69 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 19910914044441A](https://openairdocs.org/incident/19910914044441A), Sep 14, 1991: Cessna 172K, Greenville, TN, Substantial damage. On sightseeing flight overtook N73L,sheared off its left main gear with right wing,landed safely. - [Accident 19910914044442A](https://openairdocs.org/incident/19910914044442A), Sep 14, 1991: Cessna 172D, Greenville, TN, Substantial damage. On sightseeing flight was hit by N78239.had left gear sheared off by 78239,landed safely but hit parked aircraft. ## Other investigations on N78239 (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 GAA19CA014](https://openairdocs.org/ntsb/GAA19CA014), Oct 5, 2018: Cessna 172 (N78239), Stockton, CA, substantial damage. Probable cause: The student pilot's failure to maintain directional control during takeoff. 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.