# NTSB FTW96LA273: Williams Velocity 173RG, N525V, Longmont, CO, June 24, 1996 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: June 24, 1996, 09:30 local (15:30 UTC) - Place: Longmont, CO - Coordinates: 40.170047, -105.109809 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=40.1700&lon=-105.1098&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report October 4, 1996 - Report: Approved by Office Director - NTSB case key (mKey): 19881 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW96LA273 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/19881/pdf - Page: https://openairdocs.org/ntsb/FTW96LA273 ## Probable cause the pilot's improper planning/decision. Factors relating to the accident were: the high density altitude, and the pilot's inadequate weather evaluation. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Overrun, takeoff - roll/run - planning/decision - improper, pilot in command (cause) - weather condition - high density altitude (contributing factor) - weather evaluation - inadequate, pilot in command (contributing factor) - On ground/water encounter with terrain/water, takeoff ## Analysis During takeoff, the aircraft failed to achieve sufficient airspeed and overran the departure end of runway 29. Density altitude at the time was 7,500 feet. The pilot said he was aware of a high density altitude, and had purposely serviced the airplane with a partial load of fuel. Also, he noted that he had no problem on takeoff from Hattiesburg, Mississippi (elevation 151 feet) or Wichita Falls, Texas (elevation 1,005 feet), and he expected no problem during this takeoff. No pre-accident/mechanical malfunction or failure was noted during the investigation. ## Factual narrative On June 24, 1996, at 0930 mountain daylight time, an experimental home built Williams Velocity 173RG, N525V, registered to a private owner, exited the end of runway 29 onto soft ground during the takeoff roll at the Vance Brand Airport, Longmont, Colorado. The private pilot and the one passenger were not injured and the aircraft sustained substantial damage. The flight was operating under Title 14 CFR Part 91 when the accident occurred and no flight plan was filed. Visual meteorological conditions prevailed for this personal flight which was departing to Melbourne Beach, Florida, with the first en route stop planned at Salina, Kansas. According to the pilot, he was aware of the density altitude (7,500 feet) but said he had experienced no problems on takeoff from Hattiesburg, Mississippi, or Wichita Falls, Texas, on the trip to Colorado, from Florida, so he expected none on takeoff from Longmont. (Hattiesburg is 151 feet above sea level and Wichita Falls is 1,005 feet above sea level.) According to the Koch chart on altitude performance, given the conditions present at takeoff, the pilot would experience a takeoff run 130 percent longer than at sea level and climb performance would be degraded by 63 percent. No empirical data was provided by the manufacture of the kit airplane to assist the pilot in calculating takeoff and climb performance under non-standard conditions. The FAA currently does not require kit manufacturers to develop and distribute such information. The pilot stated that he was aware of density altitude and purposely had less than full fuel tanks on takeoff due to the high elevation of the airport. He reported that in the future he intended to confine his flying to airports 3,000 feet above mean sea level or less. ## Aircraft - Registration: [N525V](https://openairdocs.org/deregistered/N525V-2000-04-18), registration cancelled 2000-04-18, S/N DMO-248 (OpenAirDocs) - Reported make and model: WILLIAMS VELOCITY 173RG (VELOCITY 1) - Registry model: [Richards William A VELOCITY 173 RG](https://openairdocs.org/model/richards-william-a-velocity-173-rg) (registry code 05624YJ) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: DMO-248 - Airframe hours: 61 - Engines: Lycoming IO-360-A3B6D 200 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: William Richards - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Continuous airworthiness, March 9, 1996 - Departed: 2V2 - Destination: SLN, SALINA, KS - Airport: 2V2, Vance Brand, runway 29, 5,130 × 75 ft, concrete ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 62; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, valid medical--no waivers/lim.; seat: left; flight hours: 953 total, 80 in this make and model, 766 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Wind: 330° at 7 knots - Visibility: 30 statute miles - Lowest ceiling: none - Temperature: 70 °F, dew point 55 °F - Altimeter: 30.00 inHg - Observed at: BJC, 15 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 19960624047169A](https://openairdocs.org/incident/19960624047169A), Jun 24, 1996: Longmont, CO, Substantial damage. (-16) Airman attempted takeoff on runway too short for requirements of the aircraft. Airman admitted inadequate compensation for density altitude. Aircraft ran… ## Other investigations on N525V (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 MIA97LA078](https://openairdocs.org/ntsb/MIA97LA078), Feb 1, 1997: Richards Velocity 173 RG (N525V), Valkaria, FL, substantial damage. Probable cause: a loss of engine power for undetermined reasons. 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.