# NTSB FTW96LA380: Bell UH-1H, N23Y, Leadville, CO, September 10, 1996 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: September 10, 1996, 08:50 local (14:50 UTC) - Place: Leadville, CO - Coordinates: 39.24052, -106.289955 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.2405&lon=-106.2900&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: Serious injuries - Injuries: 1 serious, 1 minor - Status: Completed, report February 18, 1997 - Report: Approved by Office Director - NTSB case key (mKey): 19974 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW96LA380 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/19974/pdf - Page: https://openairdocs.org/ntsb/FTW96LA380 ## Probable cause The pilot's improper inflight planning/decision in that he used an inadequate airspeed or an inadequate altitude, or both, for the intentional autorotation. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight collision with terrain/water, landing - flare/touchdown - autorotation - intentional, pilot in command - in-flight planning/decision - improper, pilot in command (cause) - airspeed - inadequate, pilot in command (cause) - altitude - inadequate, pilot in command (cause) ## Analysis The helicopter crew was conducting high altitude flight tests pursuant to obtaining two Supplemental Type Certificates. From an altitude of 200 feet, and at 8,000 pounds gross weight, the pilot initiated an intentional autorotation at 42 knots with a one second delay before lowering the collective control. The pilot said he was unable to arrest the descent rate as the helicopter approached the runway at 40 knots. The helicopter was destroyed when it impacted the runway. A video camera was used to record the flight tests. A review of the tape disclosed that on at least two previous autorotations, the tail boom stinger struck the ground first. According to an FAA helicopter operations inspector, this was indicative that the pilot was 'outside the low end of the height-velocity curve.' He said that 'either there was insufficient airspeed for the altitude used, or there was insufficient altitude for the airspeed used.' ## Factual narrative On September 10, 1996, approximately 0850 mountain daylight time, a Bell UH-1H, N23Y, was destroyed during an intentional autorotation at Leadville, Colorado. The commercial pilot in command received minor injuries, and the airline transport rated-designated engineering representative (DER) sustained serious injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the test flight that originated at Leadville on September 10, approximately 0830. According to an FAA inspector, the crew was conducting high altitude flight tests pursuant to obtaining two STCs (Supplemental Type Certificates): SR000267, for the T53-L-703 engine installation, and SR00266SE, for the installation of a tractor tail rotor system from a Bell 205. According to the Pilot/Operator Aircraft Accident Report, the pilot entered an autorotation from an altitude of 200 feet agl (above ground level) and at 8,000 pounds maximum gross weight. The maneuver was entered at 42 kias (knots indicated airspeed) with a one second delay before lowering the collective control. The pilot said he was unable to arrest the descent rate as the helicopter approached the runway at 40 knots. The helicopter struck the ground tail first. A video camera was used to record the flight tests and showed impact occurring on the centerline of runway 34. The tail boom and both skids separated on impact, and the helicopter skidded on its fuselage for 370 feet before coming to a rest on the left side of the runway. The helicopter was equipped with a self sealing fuel system. There was no fire and minimal fuel spillage. Further examination of the tape revealed the tail boom stinger struck the ground on at least two previous autorotations. According to one FAA helicopter operations inspector, this was indicative that the pilot was "outside the low end of the height-velocity curve." He said that "either there was insufficient airspeed for the altitude used, or there was insufficient altitude for the airspeed used." ## Aircraft - Registration: [N23Y](https://openairdocs.org/deregistered/N23Y-1998-06-12), registration cancelled 1998-06-12, S/N 6413536 (OpenAirDocs) - Reported make and model: Bell UH-1H - Registry model: [Bell UH-1H](https://openairdocs.org/model/bell-uh-1h) (registry code 1181407) (OpenAirDocs) - Category: Helicopter - Serial number: 4243 - Airframe hours: 7403 - Engines: Lycoming T53-L-703 1485 horsepower turbo shaft - Damage: Substantial damage - Flight: Part 91 - Operator: Idaho Helicopters, Inc. - Registered owner: Farm Development Corp. - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Continuous airworthiness, August 23, 1996, 36 hours before - Departed: LXV - Flight plan: Company VFR - Airport: LXV, Lake County, runway 16, 6,400 × 75 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 46; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: helicopter, airplane; medical: class 2, valid medical--no waivers/lim.; seat: right; flight hours: 5,032 total, 1,473 in this make and model, 5,021 as pilot in command, 21 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 340° at 4 knots - Visibility: 30 statute miles - Lowest ceiling: 20,000 ft broken - Temperature: 48 °F - Altimeter: 30.00 inHg - Observed at: LXV ## 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 19960910026699A](https://openairdocs.org/incident/19960910026699A), Sep 10, 1996: Bell UH1H, Leadville, CO, Substantial damage. Helicopter was involved in auto rotation training when it crashed. 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.