# NTSB LAX99LA089: Stern Rotorway Exec 162F, N88XS, Tucson, AZ, February 5, 1999 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: February 5, 1999, 13:43 local (20:43 UTC) - Place: Tucson, AZ - Coordinates: 32.189369, -110.980712 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=32.1894&lon=-110.9807&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report November 30, 2000 - Report: Approved by Office Director - NTSB case key (mKey): 45738 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX99LA089 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/45738/pdf - Page: https://openairdocs.org/ntsb/LAX99LA089 ## Probable cause The sudden development of a wind gust which resulted in the pilot losing control, and the helicopter's dynamic rollover when a skid contacted the ground. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of control - in flight, hover - in ground effect - weather condition - crosswind - weather condition - gusts (cause) - aircraft control - not maintained, pilot in command (cause) - Roll over, hover - in ground effect - dynamic rollover - encountered, pilot in command ## Analysis After flying for about 1 hour, the student pilot hovered 2 feet above ground level about 50 yards away from a witness. The local wind speed had varied between calm and 5 knots during the flight. The witness and pilot reported that suddenly an estimated 25 knot (maximum) wind gust developed. The gust pushed the helicopter sideways, the pilot lost control, a skid contacted the ground, and the helicopter rolled over onto its side. ## Factual narrative On February 5, 1999, at 1343 hours mountain standard time, a homebuilt Rotorway Exec 162, N88XS, owned and operated by the pilot, encountered a wind gust at the Ryan Field, Tucson. The student pilot reported that he had been hovering in the area and was not having any difficulty handling the controls when suddenly he lost control, the right skid impacted the ground, and the experimental helicopter rolled over. The helicopter was substantially damaged during the flight, which was performed under 14 CFR Part 91, and the student pilot received a minor injury. Visual meteorological conditions prevailed at the time of the solo instructional flight that originated from the airport about 1230. In the pilot's report, he stated that during the hour preceding the accident the local wind speed was between 0 and 3 miles per hour. However, suddenly "a severe gust of wind (estimated at 25 - 30 mph) came from 90 degrees . . . and hit me on my left side." A witness, who was standing on the ramp about 50 yards from the accident site, reported observing the helicopter hovering 2 feet above the ground when an estimated 20 to 25 knot wind gust pushed the helicopter sideways. Thereafter, its right skid touched the ground and it rolled over. ## Aircraft - Registration: [N88XS](https://openairdocs.org/deregistered/N88XS-2013-08-08), registration cancelled 2013-08-08, S/N 6049, built 1998 (OpenAirDocs) - Reported make and model: STERN ROTORWAY EXEC 162F (ROTORWAY E) - Registry model: [Stern Lessing S ROTORWAY EXEC 162F](https://openairdocs.org/model/stern-lessing-s-rotorway-exec-162f) (registry code 05628CZ) (OpenAirDocs) - Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs) - Category: Helicopter, amateur-built - Serial number: 6049 - Airframe hours: 48 - Engines: Rotorway 162F 150 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Registered owner: Roger Lee - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, May 20, 1998, 48 hours before - Departed: RYN - Airport: RYN, Ryan Field ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 45; student; medical: class 3, valid medical--w/ waivers/lim; seat: front; flight hours: 800 total, 20 in this make and model, 20 as pilot in command, 20 in the last 90 days, 10 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 220° at 15 knots, gusting 25 - Visibility: 25 statute miles - Lowest ceiling: none - Temperature: 68 °F, dew point 30 °F - Altimeter: 30.00 inHg - Observed at: RYN ## 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 19990205001129A](https://openairdocs.org/incident/19990205001129A), Feb 5, 1999: Amtr EXEC162F, Tucson, AZ, Substantial damage. Experimental rotorway executive helicopter was involved in hover practice when a gust of wind caused the acft to strike the ground hard. Other circumstances… 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.