# NTSB CHI91FA235: Aero Commander 500B, N904DF, Silica, KS, July 31, 1991 - Type: NTSB accident investigation - Classification: Accident · Fatal · Field investigation · Final report - Date: July 31, 1991, 07:59 local (12:59 UTC) - Place: Silica, KS - Location: 38.3517° N, 98.4620° W: Placed by OpenAirDocs: center of Silica, KS, within about 6 miles (OpenAirDocs) - Nearby events: https://openairdocs.org/map.md?lat=38.3517&lon=-98.4620&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: Fatal - Injuries: 2 fatal - Status: Completed, report March 31, 1993 - Report: Approved by Office Director - NTSB case key (mKey): 14912 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI91FA235 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/14912/pdf - Page: https://openairdocs.org/ntsb/CHI91FA235 ## Probable cause (aircraft 2) THE FAILURE OF BOTH PILOTS TO MAINTAIN ADEQUATE SEPARATION DURING FORMATION FLIGHT. RELATED FACTORS ARE OVERCONFIDENCE IN PERSONAL ABILITY AND POOR PLANNING/DECISION. ## Probable cause (aircraft 1) THE FAILURE OF BOTH PILOTS TO MAINTAIN ADEQUATE SEPARATION DURING FORMATION FLIGHT. RELATED FACTORS ARE OVERCONFIDENCE IN PERSONAL ABILITY AND POOR PLANNING/DECISION. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Midair collision, maneuvering - planning/decision - poor, pilot in command (contributing factor) - overconfidence in personal ability, pilot in command (contributing factor) - planning/decision - poor, pilot of other aircraft (contributing factor) - overconfidence in personal ability, pilot of other aircraft (contributing factor) - formation flying - visual separation - not maintained, pilot in command (cause) - visual separation - not maintained, pilot of other aircraft (cause) - Midair collision, maneuvering - planning/decision - poor, pilot in command (contributing factor) - overconfidence in personal ability, pilot in command (contributing factor) - planning/decision - poor, pilot of other aircraft (contributing factor) - overconfidence in personal ability, pilot of other aircraft (contributing factor) - formation flying - visual separation - not maintained, pilot in command (cause) - visual separation - not maintained, pilot of other aircraft (cause) ## Analysis (aircraft 2) BOTH AIRCRAFT DEPARTED WICHITA ON IFR FLIGHT PLANS IN VFR WEATHER CONDITIONS. THEY FLEW NORTHWEST TOWARD THEIR RESPECTIVE DESTINATIONS, AND CANCELLED IFR ABOUT 20 MINUTES BEFORE THE ACCIDENT. ATC OBSERVED THE AIRPLANES ON RADAR, AND STATED THEY WERE 'DOGFIGHTING BACK AND FORTH' PRIOR TO THE COLLISION. ONE PILOT'S ROOMMATE REPORTED THE TWO PILOTS, WHO WERE CLOSE FRIENDS AS WELL AS CO-WORKERS, OFTEN CANCELLED IFR AND FLEW IN FORMATION IF THE WEATHER WAS VFR. HE REPORTED THE PILOTS OFTEN VIDEOTAPED EACH OTHER, AND HE HAD WATCHED SOME OF THE TAPES. HE STATED 'IT WAS HARD TO TELL FROM THE VIDEOTAPE HOW CLOSE THEY WERE BECAUSE THEY COULD USE THE ZOOM FEATURE, ETC. YOU COULD READ THE N NUMBERS.' INVESTIGATION REVEALED BROWN PAINT TRANSFER ON THE BOTTOM OF THE RIGHT WING OF THE BLUE AND WHITE AIRPLANE, WHICH HAD SEPARATED AND WAS LOCATED 1.5 MILES FROM THE MAIN WRECKAGE. THERE WERE LIGHT COLORED SCUFF MARKS ON THE TOP OF THE LEFT ENGINE NACELLE OF THE BROWN AND WHITE AIRPLANE. ## Analysis (aircraft 1) BOTH AIRCRAFT DEPARTED WICHITA ON IFR FLIGHT PLAN IN VFR WEATHER CONDITIONS. THEY FLEW NORTHWEST TOWARD THEIR RESPECTIVE DESTINATIONS, AND CANCELLED IFR ABOUT 20 MINUTES BEFORE THE ACCIDENT. ATC OBSERVED THE AIRPLANES ON RADAR, AND STATED THEY WERE 'DOGFIGHTING BACK AND FORTH' PRIOR TO THE COLLISION. ONE PILOT'S ROOMMATE REPORTED THE TWO PILOTS, WHO WERE CLOSE FRIENDS AS WELL AS CO-WORKERS, OFTEN CANCELLED IFR AND FLEW IN FORMATION IF THE WEATHER WAS VFR. HE REPORTED THE PILOTS OFTEN VIDEOTAPED EACH OTHER, AND HE HAD WATCHED SOME OF THE TAPES. HE STATED 'IT WAS HARD TO TELL FROM THE VIDEOTAPE HOW CLOSE THEY WERE BECAUSE THEY COULD USE THE ZOOM FEATURE, ETC. YOU COULD READ THE N NUMBERS.' INVESTIGATION REVEALED BROWN PAINT TRANSFER ON THE BOTTOM OF THE RIGHT WING OF THE BLUE AND WHITE AIRPLANE, WHICH HAD SEPARATED AND WAS LOCATED 1.5 MILES FROM THE MAIN WRECKAGE. THERE WERE LIGHT COLORED SCUFF MARKS ON THE TOP OF THE LEFT ENGINE NACELLE OF THE BROWN AND WHITE AIRPLANE. ## Aircraft 1 - Registration: [N904DF](https://openairdocs.org/deregistered/N904DF-1991-09-12), registration cancelled 1991-09-12, S/N 500B105746 (OpenAirDocs) - Reported make and model: AERO COMMANDER 500B - Registry model: [Aero Commander 500-B](https://openairdocs.org/model/aero-commander-500-b) (registry code 0141106) (OpenAirDocs) - Category: Airplane - Serial number: 1057-46 - Airframe hours: 11546 - Engines: LYCOMING IO-540-E1A5 290 horsepower reciprocating - Damage: Destroyed - Flight: Part 135 - Operator: Dewey E. Tower, doing business as Central Air Southwest - Airworthiness certificate: Standard, Normal - Last inspection: AAIP, June 10, 1991, 63 hours before - Departed: ICT, WICHITA, KS - Destination: HYS, HAYS, KS - Flight plan: Unknown ## Aircraft 2 - Registration: [N702CA](https://openairdocs.org/deregistered/N702CA-1991-09-10), registration cancelled 1991-09-10, S/N 500B1298113 (OpenAirDocs) - Reported make and model: AERO COMMANDER 500B - Registry model: [Aero Commander 500-B](https://openairdocs.org/model/aero-commander-500-b) (registry code 0141106) (OpenAirDocs) - Category: Airplane - Serial number: 1298-113 - Airframe hours: 12747 - Engines: LYCOMING IO-540-E1A5 290 horsepower reciprocating - Damage: Destroyed - Flight: Part 135 - Operator: Dewey E. Tower, doing business as Central Air Southwest - Airworthiness certificate: Standard, Normal - Last inspection: AAIP, July 12, 1991, 14 hours before - Departed: ICT, WICHITA, KS - Destination: GBD, GREAT BEND, KS - Flight plan: Unknown ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot, aircraft N904DF; age 35; flight instructor, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; toxicology performed; flight hours: 3,358 total, 724 in this make and model, 3,358 as pilot in command, 143 in the last 90 days, 48 in the last 30 days, 4 in the last 24 hours - Pilot, aircraft N702CA; age 26; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: left; toxicology performed; flight hours: 1,590 total, 322 in this make and model, 1,590 as pilot in command, 73 in the last 90 days, 22 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 15 statute miles - Lowest ceiling: none - Temperature: 79 °F ## 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 19910731030772A](https://openairdocs.org/incident/19910731030772A), Jul 31, 1991: Gulstm 500B, Silica, KS, Destroyed, 1 fatal. Collided in flight with company 500B W702CA. Both fell to ground. Were observed flying formation and dog fighting. - [Accident 19910731030771A](https://openairdocs.org/incident/19910731030771A), Jul 31, 1991: Gulstm 500B, Silica, KS, Destroyed, 1 fatal. Collided in flight with company 500B N904DF. Both fell to ground. Were observed flying formation and dog fighting. 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.