# NTSB FTW97LA226: Robinson R22 Beta, N4041W, San Antonio, TX, June 14, 1997 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: June 13, 1997, 19:35 local (Jun 14, 1997, 00:35 UTC) - Place: San Antonio, TX - Coordinates: 29.539806, -98.489593 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=29.5398&lon=-98.4896&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report February 2, 1998 - Report: Approved by Office Director - NTSB case key (mKey): 20246 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW97LA226 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/20246/pdf - Page: https://openairdocs.org/ntsb/FTW97LA226 ## Probable cause The flight instructor's inadequate supervision during the practice autorotation and his failure to maintain rotor RPM. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Hard landing, landing - flare/touchdown - autorotation - initiated, dual student - directional control - improper, dual student - supervision - inadequate, pilot in command(cfi) (cause) - rotor rpm - not maintained, pilot in command(cfi) (cause) ## Analysis The flight instructor was instructing the student pilot in straight-in power recovery autorotations to the center sod. The student initiated the maneuver from an altitude of 1,100 feet MSL, and an airspeed of 65 KIAS, with the rotor RPM in the 'green.' During the autorotation, at 40 feet AGL, the student initiated a cyclic flare. 'As the flare continued, the descent rate slowed.' The student 'started to apply forward cyclic to level the helicopter when it started a left yaw.' The flight instructor got on the controls to align the aircraft with the landing direction, and the low rotor RPM warning horn activated. He 'rolled on the throttle and the helicopter yawed quickly to the right.' After he corrected for the yaw the helicopter 'fell approximately 10 to 15 feet straight down.' It 'impacted [the ground] hard to where the skids were spread out and the seats were collapsed down.' ## Factual narrative On June 13, 1997, at 1935 central daylight time, a Robinson R22 Beta helicopter, N4041W, registered to the Charlie Lima Corporation and operated by Helicopter Experts as a Title 14 CFR Part 91 instructional flight, was substantially damaged during a practice autorotation at the Stinson Municipal Airport near San Antonio, Texas. Visual meteorological conditions prevailed, and a flight plan was not filed for the local flight. The certificated flight instructor and student pilot were not injured. The flight originated from the San Antonio International Airport, about 35 minutes before the accident. The flight instructor reported to the investigator-in-charge that he was instructing the student pilot in straight-in power recovery autorotations to the Stinson Municipal Airport's center sod. The student initiated the maneuver from an altitude of 1,100 feet MSL, and an airspeed of 65 KIAS, with the rotor RPM in the "green." During the autorotation, at 40 feet AGL, the student initiated a cyclic flare. "As the flare continued, the descent rate slowed." The student "started to apply forward cyclic to level the helicopter when it started a left yaw." The student told the flight instructor that he tried to roll the throttle on after leveling the helicopter; however, there was no engine response. The flight instructor got on the controls and aligned the aircraft with the landing direction, and the low rotor RPM warning horn activated. He then "rolled on the throttle and the helicopter yawed quickly to the right." After he corrected for the yaw, the helicopter "fell approximately 10 to 15 feet straight down." It "impacted [the ground] hard to where the skids were spread out and the seats were collapsed down." The flight instructor also reported that the fuel sample he took from the fuel tank had some water. A fuel sample was again taken after the accident and water was found in that sample. Examination of the helicopter by a FAA inspector revealed the skids were "stressed beyond allowable limits," and their attaching points were twisted. Both upper and lower welded frame assemblies sustained damaged. Examination of the helicopter by the manufacturer revealed that there was no water in the fuel tank or carburetor, and continuity was established to all of the valves. For practice autorotation with power recovery (below 4,000 feet), the helicopter's flight manual states, "At about 8 feet AGL, apply forward cyclic to level ship and raise collective to stop descent. Add throttle as required to keep RPM in green arc." ## Aircraft - Registration: N4041W (not matched to a registry record) - Reported make and model: Robinson R22 BETA - Category: Helicopter - Serial number: 1666 - Airframe hours: 2151 - Engines: Lycoming O-320-B2C 160 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: Helicopter Experts - Registered owner: Charlie Lima Corporation - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, May 20, 1997, 52 hours before - Departed: SAT - Airport: SSF, Stinson Municipal ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 44; commercial, private, flight instructor; airplane ratings: single-engine land; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 669 total, 512 in this make and model, 572 as pilot in command, 180 in the last 90 days, 147 in the last 30 days, 6 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 90 °F ## 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 19970613023279A](https://openairdocs.org/incident/19970613023279A), Jun 13, 1997: Robsin R22BETA, San Antonio, TX, Substantial damage. (.4)The flight instructor was instructing the student pilot in straight-in power recovery autorotations to the center sod. The student initiated the maneuver… 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.