# NTSB LAX00LA071: Rotorway Exec 90, N89678, Chandler, AZ, January 4, 2000 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: January 4, 2000, 14:00 local (21:00 UTC) - Place: Chandler, AZ - Coordinates: 33.266666, -111.800003 - Nearby events: https://openairdocs.org/map.md?lat=33.2667&lon=-111.8000&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report November 25, 2003 - Report: Approved by Office Director - Parties: Federal Aviation Administration - NTSB case key (mKey): 48462 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX00LA071 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/48462/pdf - Page: https://openairdocs.org/ntsb/LAX00LA071 ## Probable cause the fatigue fracture and separation of the secondary drive shaft, which resulted from the manufacturer's inadequate quality control process. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, approach - vfr pattern - final approach - inadequate quality control, manufacturer (cause) - rotor drive system,tail rotor drive shaft - fractured (cause) - Forced landing, emergency descent/landing - autorotation - initiated, pilot in command(cfi) - Hard landing, landing - flare/touchdown - misc rotorcraft,main rotor/tail boom contact ## Analysis The flight was a familiarization for the private pilot, who was transitioning into this model of helicopter. An approach was being made to runway 03 when the instructor heard a loud bang from the engine compartment behind his back at an altitude of 100 feet. He stated that it felt like all engine power was lost. When the instructor saw the rotor rpm decreasing, he took control and initiated an autorotation to a soft sandy area. During the touchdown, the main rotor blades contacted the tail boom, and the tail rotor blades contacted the ground. The operator reported that a subsequent inspection determined that the secondary drive shaft fractured. Laboratory examination concluded that the shaft failed from fatigue, originating from galling sites introduced during the manufacturing process. The operator reported that a temperature strip on the bearing was noted to be darkened before the flight, but they were unsure if this information was determined independantly by either the CFI or the student. All other shafts in the operator's fleet were inspected and no additional suspect shafts were found. ## Factual narrative On January 4, 2000, about 1400 mountain standard time, an amateur built experimental Rotorway Exec 90 helicopter, N89678, sustained substantial damage when the main rotor blades contacted the tail boom during an autorotation at Memorial Airport near Chandler, Arizona. The autorotation followed a failure of a shaft in the engine to rotor drive system. Rotorway International operated the helicopter under the provisions of 14 CFR Part 91. The certified flight instructor (CFI) and private pilot student were not injured. The instructional flight departed Stellar Air Park, near Chandler, about 1320. Visual meteorological conditions prevailed and no flight plan was filed. The Safety Board was notified of the accident on January 12, 2000. The operator stated the flight was a familiarization for the private pilot, who was transitioning into this model of helicopter. An approach was being made to runway 03 when the instructor heard a loud bang from the engine compartment behind his back at an altitude of 100 feet. He stated that it felt like all engine power was lost. When the instructor saw the rotor rpm decreasing, he took control and initiated an autorotation to a soft sandy area. During the touchdown, the main rotor blades contacted the tail boom, and the tail rotor blades contacted the ground. The operator reported that a subsequent inspection determined that the secondary drive shaft fractured. Laboratory examination concluded that the shaft failed from fatigue, originating from galling sites introduced during the manufacturing process. The operator reported that a temperature strip on the bearing was noted to be darkened before the flight, but they were unsure if this information was determined independantly by either the CFI or the student. All other shafts in the operator's fleet were inspected and no additional suspect shafts were found. ## Aircraft - Registration: [N89678](https://openairdocs.org/deregistered/N89678-2001-06-26), registration cancelled 2001-06-26, S/N R.I. 5026 (OpenAirDocs) - Reported make and model: Rotorway Exec 90 (EXEC 9) - Registry model: [Cobb Intl Inc DBA Rotorway INT ROTORWAY EXEC 90](https://openairdocs.org/model/cobb-intl-inc-dba-rotorway-int-rotorway-exec-90) (registry code 13017LM) (OpenAirDocs) - Category: Helicopter, amateur-built - Serial number: RI5026 - Airframe hours: 1537 - Engines: Rotorway 162F 150 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Registered owner: Cobb International - Airworthiness certificate: Special, Experimental (Special) - Last inspection: 100 hour, December 16, 1999, 8 hours before - Departed: P19, CHANDLER, AZ - Airport: Memorial, runway 3, 5,000 × 120 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 32; injuries: none; commercial, private, flight instructor; airplane ratings: single-engine land; instrument ratings: helicopter; medical: class 2, valid medical--no waivers/lim.; last flight review December 6, 1999; seat: front; flight hours: 376 total, 162 in this make and model, 307 as pilot in command, 182 in the last 90 days, 44 in the last 30 days, 2 in the last 24 hours - Student pilot; age 41; injuries: none; private; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; last flight review September 12, 1998; seat: front; flight hours: 580 total, 4 in this make and model, 545 as pilot in command, 19 in the last 90 days, 14 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 340° at 6 knots - Visibility: 30 statute miles - Lowest ceiling: none - Temperature: 63 °F, dew point 16 °F - Altimeter: 30.00 inHg - Observed at: IWA ## 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 20000104000899A](https://openairdocs.org/incident/20000104000899A), Jan 4, 2000: Amtr ROTORWAYEXEC, Chandler, AZ, Substantial damage. (.19) On January 4, 2000, about 1400 hours mountain standard time, an amateur built experimental rotorway exec 9 helicopter, N89678, sustained substantial… ## Other investigations on N89678 (3) 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 LAX96LA210](https://openairdocs.org/ntsb/LAX96LA210), May 22, 1996: Rotorway Exec 9 (N89678), Chandler, AZ, substantial damage. Probable cause: a loss of engine power due to a failed piston and piston ring in a critical phase of flight. - [NTSB LAX94LA069](https://openairdocs.org/ntsb/LAX94LA069), Dec 8, 1993: Rotorway EXEC-90 (N89678), Chandler, AZ, substantial damage. Probable cause: THE FLIGHT INSTRUCTOR'S FAILURE TO PROPERLY FOLLOW THE AIRCRAFT BALLASTING PROCEDURES THAT RESULTED IN A LOSS OF CONTROL WHEN THE HELICOPTER'S CENTER OF GRAVITY LIMITS WERE EXCEEDED. INADEQUATE… - [NTSB LAX93LA111](https://openairdocs.org/ntsb/LAX93LA111), Feb 9, 1993: Cobb Intl Exec 90 (N89678), Chandler, AZ, substantial damage. Probable cause: THE MANUFACTURER'S INADEQUATE QUALITY CONTROL WHICH RESULTED IN THE FATIGUE OF THE VALVE STEM. THE SOFT TERRAIN CONTRIBUTED TO THIS ACCIDENT. 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.