# NTSB LAX96LA210: Rotorway Exec 9, N89678, Chandler, AZ, May 22, 1996 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: May 22, 1996, 10:15 local (17:15 UTC) - Place: Chandler, AZ - Coordinates: 33.320713, -111.819206 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=33.3207&lon=-111.8192&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report August 20, 1996 - Report: Approved by Office Director - NTSB case key (mKey): 29452 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX96LA210 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/29452/pdf - Page: https://openairdocs.org/ntsb/LAX96LA210 ## Probable cause a loss of engine power due to a failed piston and piston ring in a critical phase of flight. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(partial) - mech failure/malf, landing - flare/touchdown - engine assembly,ring - failure,total (cause) - engine assembly,piston - cracked (cause) - Hard landing, landing - flare/touchdown - Other gear collapsed, landing - flare/touchdown - landing gear,skid assembly - overload - Roll over, landing - flare/touchdown ## Analysis The dual student began to apply power during a normal approach to landing when the main rotor rpm needle went into the yellow arc on the engine gauge. The CFI applied full power but the rpm continued into the lower portion of the arc. The helicopter made ground contact with low rotor rpm and the right skid collapsed. The helicopter bounced and rolled over. Examination of the engine revealed that a section of the piston from the dome to the first ring groove had broken away. The upper ring was broke and pieces were found in the combustion area. Normal carbon buildup was found on the cylinder sleeve above the top ring surface except in the area of the piston breakage, indicating that the engine had been operating for a period of time after the damage had taken place and before the accident. ## Factual narrative On May 22, 1996, at 1015 hours mountain standard time, a Rotorway Exec 9 experimental helicopter, N89678, turned over during a normal approach to landing at Chandler, Arizona. The aircraft sustained substantial damage and the two pilots onboard were not injured. Visual meteorological conditions existed at the time and no flight plan was filed for the local instructional flight. According to the instructor pilot, he set up for a normal landing into the wind from an altitude of 500 feet agl. He began an application of power at 40 feet agl when the main rotor rpm needle entered the yellow (arc). With a full application of power, the rpm continued to the lower portion of the yellow arc. The helicopter made ground contact with low rotor rpm. The aircraft yawed to the right and the pilot applied full right pedal. On initial ground contact the right skid collapsed and the aircraft bounced, turned, and rolled over. The pilot reported a left quartering wind at the time. The pilot stated the terrain was flat and level, and he had used this landing site before. He reported no mechanical malfunctions with the aircraft prior to the accident. The engine was examined and a report was submitted from Rotorway International. They reported that the upper edge of the number 1 piston (approximately 1/8 of its diameter) was broken away down to the top of the piston ring groove. The upper ring was broke and pieces were found in the combustion chamber. They reported there were no signs of the ring or piston in the cylinder and that all pieces had exited the exhaust port. The report further states that carbon build up on the cylinder sleeves above the top ring surface was normal except in the area of the piston breakage. To them, this indicated the engine was operating for some time before the damage had been noticed. Also, the cylinder was found out of round beyond normal specifications. ## 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 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 - Serial number: RI 5026 - Engines: Rotorway 162 150 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Registered owner: Cobb International, Inc - Airworthiness certificate: Special, Experimental (Special) - Last inspection: 100 hour, May 22, 1996, 3 hours before - Departed: P19 ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 49; flight instructor, commercial; airplane ratings: single-engine land, single-engine sea; medical: class 2, valid medical--w/ waivers/lim; seat: right; flight hours: 797 total, 172 in this make and model, 643 as pilot in command, 151 in the last 90 days, 61 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Visibility: 30 statute miles - Lowest ceiling: none ## 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 19960522012139A](https://openairdocs.org/incident/19960522012139A), May 22, 1996: Amtr ROTORWAYEXEC, Chandler, AZ, Substantial damage. Landed hard due low rotor RPM. Folded skid. Rolled over. NR1 piston top broke off. Engine operated defect in piston ## 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 LAX00LA071](https://openairdocs.org/ntsb/LAX00LA071), Jan 4, 2000: Rotorway Exec 90 (N89678), Chandler, AZ, substantial damage. Probable cause: the fatigue fracture and separation of the secondary drive shaft, which resulted from the manufacturer's inadequate quality control process. - [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.