# NTSB FTW98LA327: Robinson R22 Beta, N8350N, Englewood, CO, July 22, 1998 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: July 22, 1998, 14:20 local (20:20 UTC) - Place: Englewood, CO - Coordinates: 39.580097, -104.860504 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.5801&lon=-104.8605&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 2 minor - Status: Completed, report February 16, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 43177 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW98LA327 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/43177/pdf - Page: https://openairdocs.org/ntsb/FTW98LA327 ## Probable cause An encounter with unanticipated windshear or a downdraft. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight encounter with weather, maneuvering - weather condition - windshear (cause) - weather condition - downdraft (cause) - In flight collision with terrain/water, descent ## Analysis The instructor and his student were practicing 180 degree autorotations, preparing for the student's commercial and flight instructor checkrides. The maneuvers were begun between 610 and 660 feet above the ground. They completed several autorotations without incident. The instructor said the helicopter dipped slightly as airspeed increased by 5 knots to 65-70 knots indicated. Main rotor rpm decreased slightly, so he made an aft cyclic input and lowered collective slightly. Rate of descent suddenly increased rapidly and the instructor decreased bank angle with cyclic, increased power, and raised the collective. He flared to arrest the rate of descent as much as possible and pulled collective to cushion the landing. The instructor said he thought wind shear or a strong downdraft caused the accident. ## Factual narrative On July 22, 1998, approximately 1420 mountain daylight time, a Robinson R22 Beta, N8350N, was destroyed while maneuvering 1 mile east of Centennial Airport, Englewood, Colorado. The flight instructor and his private pilot-certificated student received minor injuries. The instructional flight was being operated by XL Helicopters Inc. under Title 14 CFR Part 91. Visual meteorological conditions prevailed at the time of the accident, and no flight plan had been filed. The flight originated approximately 1400. According to the instructor-pilot's accident report, he and his student were practicing 180 degree autorotations, preparing for the student's commercial and flight instructor checkrides. The maneuvers were begun between 610 and 660 feet above the ground. They completed several autorotations without incident. The instructor said that during the autorotation that culminated in the accident, both he and his student were operating the controls because he wanted to demonstrate another way of entering the (180 degree) turn. He said the helicopter "dipped slightly as our airspeed increased by maybe 5 knots, to 65-70 knots indicated. The main rotor rpm decreased slightly, so I made an aft cyclic input and lowered collective slightly, but it didn't seem to completely correct the attitude/airspeed, although I believe rpm increased. At this point, the rate of descent suddenly increased very, very rapidly. I decreased our bank angle with cyclic and. . .rolled throttle back on to re-engage the power and raised the collective. . .and aft cyclic. I remember flaring to get rid of as much of our rate of descent as possible. I vaguely remember pulling collective to cushion the landing." Citing a fast-moving thunderstorm that occurred 90 to 120 minutes after the accident, the instructor said he thought wind shear or a strong downdraft caused the accident. Centennial control tower reported the accident at 1420. In his accident report, the pilot indicated the accident occurred approximately 1515. The METAR observation made at 1553 was as follows: Wind 060 degrees at 9 kts; visibility 10 sm; ceiling 4,500 ft. broken, 8,000 ft. broken; 25,000 ft. broken; temperature 24 degrees C. (75.2 degrees F.); dew point 16 degrees C. (60.8 degrees F.); altimeter 30.22 in. Hg.; Remarks: rain began 1505, rain ended 1528; sea level pressure 1016.6 mb; mountains obscured southwest through northwest. ## Aircraft - Registration: N8350N (not matched to a registry record) - Reported make and model: Robinson R22 BETA - Category: Helicopter - Serial number: 2704 - Airframe hours: 636 - Engines: Lycoming O-360-J2A 131 horsepower reciprocating - Damage: Destroyed - Flight: Instructional, Part 91 - Registered owner: Xl Helicopters Inc. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, July 7, 1998, 39 hours before - Departed: APA, ENGLEWOOD, CO ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 33; commercial, flight instructor; medical: class 2, valid medical--no waivers/lim.; seat: right; flight hours: 1,079 total, 1,068 in this make and model, 991 as pilot in command, 170 in the last 90 days, 54 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 60° at 9 knots - Visibility: 10 statute miles - Lowest ceiling: 4,500 ft broken - Temperature: 75 °F, dew point 61 °F - Altimeter: 30.00 inHg - Observed at: APA, 1 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 19980722016859A](https://openairdocs.org/incident/19980722016859A), Jul 22, 1998: Robsin R22BETA, Denver, CO, Destroyed. (-23) The instructor and student were performing autorotations between 200 and 300 feet above the ground. 4 to 5 autorotations were completed without incident.… 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.