# NTSB WPR18LA041: Robinson Helicopter R22, N47WH, Truckee, CA, November 30, 2017 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Class 3 · Limited · Final report - Date: November 30, 2017, 15:35 local (23:35 UTC) - Place: Truckee, CA · Airport environment - helicopter landing pad - Coordinates: 39.319999, -120.13944 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.3200&lon=-120.1394&mi=10 - Phase of flight: [Emergency descent](https://openairdocs.org/ntsb-phases/600) (OpenAirDocs' grouping) - Defining event: [Autorotation: Hard landing](https://openairdocs.org/ntsb-events/092) - Highest injury: Serious injuries - Injuries: 2 serious - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration, Robinson Helicopter Company - NTSB case key (mKey): 96411 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR18LA041 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/96411/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=96411 - Page: https://openairdocs.org/ntsb/WPR18LA041 ## Probable cause The flight instructor’s failure to execute a power recovery from a non-stabilized autorotative descent, which resulted in a hard landing. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters: prop/rotor parameters](https://openairdocs.org/ntsb-findings/01062052): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Robinson Helicopter R22, 4 cases](https://openairdocs.org/ntsb-findings/01062052/cases.md?model=7640102), [All aircraft, 182 cases](https://openairdocs.org/ntsb-findings/01062052/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Instructor/check pilot (probable cause); cases with it: [Robinson Helicopter R22, 18 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=7640102), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Performance/control parameters: landing flare](https://openairdocs.org/ntsb-findings/01062041): Aircraft › Aircraft oper/perf/capability · Attain/maintain not possible (probable cause); cases with it: [Robinson Helicopter R22, 3 cases](https://openairdocs.org/ntsb-findings/01062041/cases.md?model=7640102), [All aircraft, 1,285 cases](https://openairdocs.org/ntsb-findings/01062041/cases.md) - [Performance/control parameters: descent rate](https://openairdocs.org/ntsb-findings/01062037): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Robinson Helicopter R22, 5 cases](https://openairdocs.org/ntsb-findings/01062037/cases.md?model=7640102), [All aircraft, 242 cases](https://openairdocs.org/ntsb-findings/01062037/cases.md) - [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Instructor/check pilot (probable cause); cases with it: [Robinson Helicopter R22, 7 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md?model=7640102), [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Autorotation: Hard landing](https://openairdocs.org/ntsb-events/092) (defining event); cases with it: [Robinson Helicopter R22, 13 cases](https://openairdocs.org/ntsb-events/092/sequence.md?model=7640102), [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md) - [Autorotation: Attempted remediation/recovery](https://openairdocs.org/ntsb-events/060); cases with it: [Robinson Helicopter R22, 6 cases](https://openairdocs.org/ntsb-events/060/sequence.md?model=7640102), [All aircraft, 1,422 cases](https://openairdocs.org/ntsb-events/060/sequence.md) ## Analysis The flight instructor was demonstrating an autorotation with a 180° left turn at a density altitude of about 6,470 ft. He entered the maneuver from 700 ft above ground level (agl) and about 80 kts indicated airspeed, established engine rpm, and started the 180° turn. About 1/3 of the way through the turn, he felt he needed a “desirable” speed through the turn and moved the cyclic forward and adjusted the collectively accordingly. The flight instructor stated that when he should have been 2/3 through the turn, he felt that he did not have the cyclic and collective control of the helicopter and he knew they were going to crash. He further stated that he continued “teaching,” and called out “rpm, airspeed, and outside,” while pointing to the tachometer, airspeed indicator, and intended landing spot; he also made control inputs and continued to fly what “had become an unresponsive aircraft.” He also stated that there was no flare at the end of the autorotation and no time for an engine rpm recovery. Postaccident examination of the airframe and engine revealed no mechanical anomalies that would have precluded normal operation. The helicopter manufacturer’s Safety Notice SN-38 stated that if any of the parameters for rotor rpm, a stabilized airspeed, a stabilized rate of descent or turns (if any) completed are not correct, an immediate power recovery should be initiated; salvaging the situation by coaching the student or trying to correct below 100 ft agl (200 ft when operating at or above 4000 ft density altitude) should not be attempted. Had the flight instructor aborted the autorotation early on, it is likely he would have regained helicopter control. ## Factual narrative On November 30, 2017, at 1540 Pacific standard time, a Robinson Helicopter Company (RHC) R22, N47WH, was substantially damaged when it was involved in an accident near Truckee, California. The two pilots were seriously injured. The helicopter was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The flight instructor reported that the pilot/owner had just purchased the helicopter and it was delivered the morning of the accident. The flight instructor had flown the helicopter earlier in the day to comply with his recent flight experience requirements. The accident occurred in the afternoon, with the owner of the helicopter also onboard. The purpose of the afternoon flight was to check out the flight characteristics with two full size adults on board to determine if it could serve as a viable training helicopter for the operator. If the helicopter performed well, then he and the owner would practice some procedures and maneuvers required for a biennial flight review for the owner. According to the flight instructor they practiced several different maneuvers, normal takeoffs, pattern work, normal approaches, steep approaches, landings, hover work, governor off work, hovering autorotations, and low rpm recovery in a hover. The flight instructor stated that the flight went well, and they decided to do straight-in autorotations as well as 180° autorotations. After completion of the straight-in autorotations, they moved on to 180° autorotations. The flight instructor set up for a 180° autorotation; while on downwind they commented that the helicopter was not flying smoothly and thought the main rotor was unbalanced and had a “little hop.” He had not noticed the vibration on the earlier flights. They continued with the flight and the maneuver. After they passed the intended landing point, he entered from 700 ft above ground level (agl) and about 80 kts indicated airspeed, he established his rpm, and started the 180° turn. About 1/3 of the way through the turn, he felt he needed a “desirable” speed through the turn and moved the cyclic forward and adjusted the collectively accordingly. The flight instructor stated that when he should have been 2/3 through the turn, he felt that he did not have the cyclic and collective control of the helicopter and he knew they were going to crash. He further stated that he continued “teaching,” and called out “rpm, airspeed, and outside,” while pointing to the tachometer, airspeed indicator, and intended landing spot; he also made control inputs and continued to fly what “had become an unresponsive aircraft.” The flight instructor stated that there was no flare at the end of the autorotation and no time for an engine rpm recovery. A witness at the airport watched the helicopter practicing pattern work east of runway 29. He saw the helicopter turn onto its base leg at a normal attitude and then it entered a rapid descent toward the runway. The witness reported that the helicopter flaredabout 30 yards from the runway, impacted the ground, tail rotor first, followed by the main body of the helicopter. The main rotor blades sheared off the tail boom and the helicopter came to rest on its side. Postaccident examination of the airframe established flight control continuity. The tail cone separated after contact by a main rotor blade. The throttle linkage was intact and in the closed position. The mixture was full rich, and the carburetor heat was in the OFF position. Both V-belts were out of the sheave grooves. One V-belt was fractured across the vees. The fuel tanks were half-full as verified visually and by the fuel gauges. The engine sustained minimal impact damage. The crankshaft rotated by hand using the cooling fan with no anomalies noted. Thumb compression was established in all cylinders, and spark was produced at the lower ignition leads during rotation of the crankshaft. The automated weather observation station at the Truckee-Tahoe Airport (TRK), Truckee, California, reported at 1545 wind from 290° at 5 knots, temperature 50°, dewpoint 23°, and altimeter setting of 30.17 inches of mercury. TRK was located at an elevation of 5,904.3 ft mean sea level (msl); density altitude was calculated to be 6,469 ft. The maximum gross takeoff weight for the R22 Beta II is 1,370 lbs. The estimated gross weight at the time of the accident was calculated to be about 1,356 lbs. Information pertaining to the execution of autorotations can be found in the Helicopter Flying Handbook, as well as the FAA Practical Test Standard, Private Pilot Rotorcraft, along with additional information from RHC Safety Notice SN-38, Practice Autorotations Cause Many Training Accidents. SN-38, in part, indicated a 100 ft decision check that identified rotor rpm, stabilized airspeed, stabilized rate of descent, and turns. An immediate power recovery should be made if any of the parameters are not correct. It also stated that there should be no attempt to salvage the situation by coaching the student or trying to correct below 100 ft above ground level (agl). At density altitudes above 4,000 ft, the decision height should be increased to 200 ft above the ground or higher. The safety notice also indicated that practice should be limited to no more than three or four consecutive autorotations to maintain instructor focus and minimize student fatigue. ## Aircraft - Registration: [N47WH](https://openairdocs.org/deregistered/N47WH-2018-09-13), registration cancelled 2018-09-13, S/N 3525, built 2003 (OpenAirDocs) - Reported make and model: ROBINSON HELICOPTER COMPANY R22 (MARINER) - Registry model: [Robinson Helicopter R22](https://openairdocs.org/model/robinson-helicopter-r22) (registry code 7640102) (OpenAirDocs) - Registry engine: [Lycoming O-360 series](https://openairdocs.org/engine/lycoming-o-360-series) (registry code 41575, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 3525 - Year built: 2003 - Airframe hours: 219 - Engines: LYCOMING O-360-J2A 145 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Tumbleweed Leasing Co Inc - Registered owner: Tumbleweed Leasing Co Inc - Airworthiness certificate: Standard, Normal - Destination: Same as departure - Airport: TRK, Truckee-Tahoe - Equipment: Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 52; injuries: serious; flight instructor, commercial; instrument ratings: helicopter; medical: class 2, with waivers/limitations; last flight review May 15, 2017; seat: left; restraint: 3-point; flight hours: 5,889 total, 1,142 in this make and model, 54 in the last 90 days, 30 in the last 30 days, 1 in the last 24 hours - Student pilot; age 38; injuries: serious; commercial; instrument ratings: helicopter; medical: class 2, without waivers/limitations; last flight review October 10, 2017; seat: right; restraint: 3-point; flight hours: 2,200 total, 180 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 290° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: 24,000 ft broken - Temperature: 50 °F, dew point 23 °F - Altimeter: 30.17 inHg - Observed at: KTRK - METAR: METAR KTRK 302345Z 29005KT 10SM SCT017BKN240 10/M05 A3017= ## Other investigations on N47WH (1) 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. - [NTSB WPR12CA307](https://openairdocs.org/ntsb/WPR12CA307), Jul 16, 2012: Robinson Helicopter R22 (N47WH), Bountiful, UT, substantial damage. Probable cause: The student’s failure to maintain adequate rotor rpm and the flight instructor’s delayed remedial action, which resulted in a hard landing. ## Docket (12 files) The files NTSB released with the investigation on March 18, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=96411. 30.5 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 12 pages, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12872106&FileExtension=pdf&FileName=WPR18LA041%206120_Redacted-Rel.pdf - Pilot's statement (item 2, PDF, 3 pages, 100 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13418160&FileExtension=pdf&FileName=pilot%20statements_Redacted-Rel.pdf - Trk metars (item 3, PDF, 2 pages, 122 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13394925&FileExtension=pdf&FileName=Display%20metars-Rel.pdf - Record of conversation (FAA) (item 4, PDF, 2 pages, 124 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12872225&FileExtension=pdf&FileName=MHinzman%20RoC_Redacted-Rel.pdf - Summary of findings FAA (item 5, PDF, 2 pages, 186 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12872462&FileExtension=pdf&FileName=Summary%20of%20Findings%20WGeyer%20FAA_Redacted-Rel.pdf - Density altitude calculation (item 6, PDF, 3 pages, 197 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13394266&FileExtension=pdf&FileName=Density%20Altitude%20Calculator%20TRK-Rel.pdf - Rhc report (item 7, PDF, 116 pages, 26.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13393575&FileExtension=pdf&FileName=RHC%20N47WH%20Accident%20Report_Redacted-Rel.pdf - Excerpt rhc report wt & bal (item 8, PDF, 1 page, 88 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13394817&FileExtension=pdf&FileName=Excerpt%20RHC%20N47WH%20Accident-Rel.pdf - Rhc POH section 4 normal procedures - practice autorotations power recovery (item 9, PDF, 1 page, 335 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13416847&FileExtension=pdf&FileName=R22%20POH%204%20normal%20procedures%20practice%20auto%20power%20recovery-Rel.pdf - Rhc safety notice 38 practice autorotations may cause many training accidents (item 10, PDF, 1 page, 91 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13308315&FileExtension=pdf&FileName=RHC%20Saafety%20Notice%2038%20Practice%20Autorotations%20May%20Cause%20Many%20Training%20Accidents-Rel.pdf - Statement of party representatives to NTSB investigation (item 11, PDF, 1 page, 260 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12871849&FileExtension=pdf&FileName=Party%20form%20%20%20%20%20%20132_Redacted-Rel.pdf - Photos (FAA) (item 12, PDF, 2 pages, 1.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13060113&FileExtension=pdf&FileName=Photos%20FAA-Rel.pdf 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.