# NTSB DEN99LA058: Robinson R22 Beta, N8354Z, Englewood, CO, March 25, 1999 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: March 25, 1999, 16:30 local (23:30 UTC) - Place: Englewood, CO - Coordinates: 39.579627, -104.859779 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.5796&lon=-104.8598&mi=10 - Phase of flight: [Emergency descent](https://openairdocs.org/ntsb-phases/600) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report May 8, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 45977 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN99LA058 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/45977/pdf - Page: https://openairdocs.org/ntsb/DEN99LA058 ## Probable cause The flight instructor allowed the rotor rpm to decay during an autorotation which resulted in a hard landing. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Hard landing, descent - emergency - autorotation - performed, pilot in command(cfi) - rotor rpm - not maintained, pilot in command(cfi) (cause) - terrain condition - open field ## Analysis The flight instructor and his student were practicing autorotations. The entry was made at 700 feet above the ground (agl), and the turn was completed at approximately 200 agl. As the helicopter rolled out of the turn, the collective was lowered 'but not enough,' and the rpm continued to decay. At the end of the flare, approximately 20-25 feet agl, a high sink rate began to build. The instructor took control and rolled the throttle to recover the rpm but did not have sufficient altitude or rpm. The helicopter impacted the ground hard in a level attitude. Upon impact, the skids buckled outward and the main rotor blades flexed downward, severing the tail boom. ## Factual narrative On March 25, 1999, approximately 1630 mountain standard time, a Robinson R22 Beta helicopter, N8354Z, operated by HL Helicopters of Boulder, Colorado, was substantially damaged while maneuvering 7 miles south of Englewood, Colorado. The airline transport rated flight instructor and his private pilot-certificated student were not injured. The aircraft was being operated under Title 14 CFR Part 91, and no flight plan had been filed. Visual meteorological conditions prevailed for the local area instructional flight that originated from Centennial Airport, Englewood, Colorado, 30 minutes before the accident. According to the flight instructor, he was teaching autorotations to his student along a large, flat plateau. After completing one straight and one 180 degree autorotation, the student was attempting a second 180 degree autorotation. The entry was made at 700 feet above the ground (agl), and the turn was completed at approximately 200 agl. He stated that a large collective increase was required during the turn due to the high bank angle necessitated by the strong wind. As the aircraft rolled out of the turn, the collective was lowered "but not enough," and the rpm continued to decay. At the end of the flare, approximately 20-25 feet agl, a high sink rate began to build. The instructor said he took control of the helicopter and rolled the throttle to recover the rpm, but did not have sufficient altitude or rpm. The helicopter impacted the ground "very hard" in a level attitude. Upon impact, the skids buckled outward and the main rotor blades flexed downward, severing the tail boom. ## Aircraft - Registration: [N8354Z](https://openairdocs.org/deregistered/N8354Z-2018-01-26), registration cancelled 2018-01-26, S/N 2723, built 1997 (OpenAirDocs) - Reported make and model: Robinson R22 BETA - Registry model: [Robinson Helicopter R22 BETA](https://openairdocs.org/model/robinson-helicopter-r22-beta) (registry code 7640110) (OpenAirDocs) - Registry engine: [Lycoming 0-360-A1D](https://openairdocs.org/engine/lycoming-0-360-a1d) (registry code 41504, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 2723 - Airframe hours: 777 - Engines: Lycoming O-360-A1D 180 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Registered owner: Xl Helicopters Inc. - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, March 1, 1999 - Departed: APA, CO ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 52; flight instructor, airline transport; airplane ratings: single-engine land; instrument ratings: airplane, helicopter; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 15,000 total, 6,000 in this make and model, 13,800 as pilot in command, 130 in the last 90 days, 32 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 140° at 20 knots, gusting 25 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 55 °F, dew point 27 °F - Altimeter: 29.00 inHg - Observed at: APA, 7 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 19990325002679A](https://openairdocs.org/incident/19990325002679A), Mar 25, 1999: Robsin R22BETA, Denver, CO, Substantial damage. (-23)Aircraft operated by xl helicopters of boulder, CO. Was substantially damaged while performing training in an area aprox. 7 miles south of englewood, CO.… 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.