# NTSB LAX96LA343: Aero Commander 690, N840DC, Truckee, CA, September 20, 1996 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: September 20, 1996, 15:45 local (22:45 UTC) - Place: Truckee, CA - Location: 39.2639° N, 120.1577° W: Placed by OpenAirDocs from NTSB’s distance and direction from TRUCKEE-TAHOE (TRK), within about a mile (OpenAirDocs) - Nearby events: https://openairdocs.org/map.md?lat=39.2639&lon=-120.1577&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report March 31, 1998 - Report: Approved by Office Director - NTSB case key (mKey): 29567 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX96LA343 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/29567/pdf - Page: https://openairdocs.org/ntsb/LAX96LA343 ## Probable cause (aircraft 2) The inadequate visual outlook by both pilots while in the vicinity of the airport. A factor was that each aircraft was on a different frequency at the time. ## Probable cause (aircraft 1) The inadequate visual lookout by both pilots while in the vicinity of the airport. A factor was that each aircraft was on a different frequency at the time. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Midair collision, climb - to cruise - communications/information/atc - not used, pilot in command (contributing factor) - visual lookout - inadequate, pilot in command (cause) - diverted attention, pilot in command - visual lookout - inadequate, pilot of other aircraft (cause) - Midair collision, maneuvering - communications/information/atc - not used, pilot in command (contributing factor) - visual lookout - inadequate, pilot in command (cause) - visual lookout - inadequate, pilot of other aircraft (cause) - diverted attention, pilot of other aircraft ## Analysis (aircraft 2) The Aero Commander 690, N840DC, collided with the Grob 102 glider, N22ZB, while climbing through 10,000 feet msl 4 miles south of the airport. The Aero Commander pilot had announced his departure on runway 28 on the unicom frequency of 122.8 Mhz while taxiing. After departing, the pilot turned left and was heading southeast in a climb. The glider had departed the airport about 1 hour earlier via aero tow and was orbiting left in a thermal. The glider pilot was monitoring the frequency 123.3 Mhz, an air-to-air frequency used by glider pilots. Moments before the collision, the Aero Commander pilot was tuning a navigation radio. He looked up and saw the glider in his windshield, but was unable to avoid the collision. The glider pilot never saw the Aero Commander. The left wing of the Aero Commander struck the left wing and fuselage of the glider about 9,800 feet msl. Both pilots were able to safely land their airplanes at the Truckee Airport after the collision. ## Analysis (aircraft 1) The Aero Commander 690, N840DC, collided with the Grob 102 glider, N22ZB, while climbing through 10,000 feet msl 4 miles south of the airport. The Aero Commander pilot had announced his departure on runway 28 on the unicom frequency of 122.8 Mhz while taxiing. After departing, the pilot turned left and was heading southeast in a climb. The glider had departed the airport about 1 hour earlier via aero tow and was orbiting left in a thermal. The glider pilot was monitoring the frequency 123.3 Mhz, an air-to-air frequency used by glider pilots. Moments before the collision, the Aero Commander pilot was tuning a navigation radio. He looked up and saw the glider in his windshield, but was unable to avoid the collision. The glider pilot never saw the Aero Commander. The left wing of the Aero Commander struck the left wing and fuselage of the glider about 9,800 feet msl. Both pilots were able to safely land their airplanes at the Truckee Airport after the collision. ## Factual narrative (aircraft 2) On September 20, 1996, at 1545 hours Pacific daylight time, an Aero Commander 690, N840DC, collided with a Grob 102 glider, N22ZB, while climbing through 10,000 feet msl in the vicinity of Truckee, California. Both aircraft sustained substantial damage and neither pilot was injured. The Aero Commander was being operated by Dempsey Construction Corporation of Ketchum, Idaho, as a business flight. The Grob 102 was operated by Soar Truckee and rented by the pilot for a local area personal flight. Visual meteorological conditions prevailed at the time. The Aero Commander pilot announced his departure on runway 28 while taxiing on the unicom frequency of 122.8 Mhz at the Truckee Airport. After departing the pilot turned left and was heading southeast in a climb. The glider departed the Truckee Airport about 1 hour earlier via aero tow and was orbiting left in a thermal in the vicinity of Lookout Mountain about 4 miles south of the Truckee Airport. The glider pilot was monitoring the frequency 123.3 Mhz, an air-to-air frequency used by glider pilots. Moments before the collision, the Aero Commander pilot was tuning a navigation radio. He looked up and saw the glider in his windshield, but was unable to avoid the collision. The glider pilot never saw the Aero Commander. The left wing of the Aero Commander struck the left wing and fuselage of the glider about 9,800 feet msl. Both pilots were able to safely land their airplanes at the Truckee Airport after the collision. ## Factual narrative (aircraft 1) On September 20, 1996, at 1545 hours Pacific daylight time, an Aero Commander 690, N840DC, collided with a Grob 102 glider, N22ZB, while climbing through 10,000 feet msl in the vicinity of Truckee, California. Both aircraft sustained substantial damage and neither pilot was injured. The Aero Commander was being operated by Dempsey Construction Corporation of Ketchum, Idaho, as a business flight. The Grob 102 was operated by Soar Truckee and rented by the pilot for a local area personal flight. Visual meteorological conditions prevailed at the time. The Aero Commander pilot announced his departure on runway 28 while taxiing on the unicom frequency of 122.8 Mhz at the Truckee Airport. After departing the pilot turned left and was heading southeast in a climb. The glider departed the Truckee Airport about 1 hour earlier via aero tow and was orbiting left in a thermal in the vicinity of Lookout Mountain about 4 miles south of the Truckee Airport. The glider pilot was monitoring the frequency 123.3 Mhz, an air-to-air frequency used by glider pilots. Moments before the collision, the Aero Commander pilot was tuning a navigation radio. He looked up and saw the glider in his windshield, but was unable to avoid the collision. The glider pilot never saw the Aero Commander. The left wing of the Aero Commander struck the left wing and fuselage of the glider about 9,800 feet msl. Both pilots were able to safely land their airplanes at the Truckee Airport after the collision. ## Aircraft 1 - Registration: [N840DC](https://openairdocs.org/deregistered/N840DC-2001-07-25), registration cancelled 2001-07-25, S/N 11661 (OpenAirDocs) - Reported make and model: Aero Commander 690 - Registry model: [Rockwell International 690C](https://openairdocs.org/model/rockwell-international-690c) (registry code 7630517) (OpenAirDocs) - Category: Airplane - Serial number: 11661 - Airframe hours: 3687 - Engines: Garrett TPE-331 717 horsepower turbo prop - Damage: Substantial damage - Flight: Business, Part 91 - Registered owner: Dempsey Construction - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, May 19, 1996, 72 hours before - Departed: TRK, TRUCKEE, CA - Destination: MMH, MAMMOTH LAKES, CA - Airport: TRK, Truckee-Tahoe Airport, runway 28, 7,000 × 100 ft ## Aircraft 2 - Registration: [N22ZB](https://openairdocs.org/aircraft/N22ZB), registered now, S/N 1309, built 1976 (OpenAirDocs) - Reported make and model: Burkhart Grob 102 - Registry model: [Burkhart Grob Flugzeugbau G102 ASTIR CS](https://openairdocs.org/model/burkhart-grob-flugzeugbau-g102-astir-cs) (registry code 1660104) (OpenAirDocs) - Registry engine: [NONE](https://openairdocs.org/engine/none) (registry code 00000, none) (OpenAirDocs) - Category: Glider - Serial number: 1309 - Engines: unknown - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Soar Truckee - Registered owner: Sebald, Leslie - Airworthiness certificate: Standard, Utility - Departed: TRK - Airport: TRK, Truckee-Tahoe Airport ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot, aircraft N840DC; age 62; private; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 3, valid medical--no waivers/lim.; seat: left; flight hours: 9,697 total, 4,112 in this make and model, 9,697 as pilot in command, 55 in the last 90 days, 22 in the last 30 days, 1 in the last 24 hours - Pilot, aircraft N22ZB; age 34; private; medical: unknown, unknown; seat: right; flight hours: 93 total, 34 in this make and model, 47 as pilot in command, 35 in the last 90 days, 10 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 230° at 9 knots - Visibility: 30 statute miles - Lowest ceiling: none - Temperature: 79 °F, dew point 37 °F - Altimeter: 30.00 inHg - Observed at: TRK, 4 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 19960920034351A](https://openairdocs.org/incident/19960920034351A), Sep 20, 1996: Gulstm 690C, Truckee, CA, Substantial damage. Tuning radio during climb through FL190, failed to see and avoid a glider that was thermaling. Wing tips hit. - [Accident 19960920034352A](https://openairdocs.org/incident/19960920034352A), Sep 20, 1996: Grob G102ASTIR, Truckee, CA, Substantial damage. While thermaling at FL190 wing tip was hit by wing tip of other aircraft climbing to cruise. Both landed safely. 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.