# Accident 19990625007629A: Amtr ROTORWAYEXEC, Los Angeles, CA, June 25, 1999

- Type: FAA accident report (Accident/Incident Data System), as reported
- Date: June 25, 1999, 15:43 local time
- Place: Los Angeles, CA
- Airport: Whiteman Airport
- Damage: Substantial damage
- Phase of flight: Autorot Descent (Rotorcraft)
- Operating rules: General operating rules (Part 91)
- Location: 34.2593° N, 118.4134° W: Placed by OpenAirDocs at WHITEMAN (WHP), within about a mile (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=34.2593&lon=-118.4134&mi=10
- Aircraft: N112WM, a cancelled registration (https://openairdocs.org/deregistered/N112WM-1999-08-31) (OpenAirDocs)
- Registry model: Miller Wayne L ROTORWAY EXEC 162F (registry code 05606YS, https://openairdocs.org/model/miller-wayne-l-rotorway-exec-162f) (OpenAirDocs)
- Reported make and model: AMTR ROTORWAYEXEC
- Fatal injuries: 0
- Pilot flight hours: 6,000 total, 15 in this make and model, 225 in the last 90 days
- NTSB investigation: [NTSB LAX99LA236](https://openairdocs.org/ntsb/LAX99LA236) (OpenAirDocs)
- FAA source: FAA Aviation Safety Information Portal (https://asip.faa.gov/)
- Page: https://openairdocs.org/incident/19990625007629A

## Narrative

As the FAA filed it, in capitals; the FAA replaces private details with ^PRIVACY DATA OMITTED^.

ACFT EXPERIENCED AN UNKNOWN EMERGENCY, MADE AN EMERGENCY LANDING NEAR OSBORNE AND NORRIS STREETS, AND SUSTAINED SUBSTANTIAL DAMAGE ON LANDING, OTHER CIRCUMSTANCES ARE UNKNOWN. (.4)THE EXPERIMENTAL HELICOPTER EXPERIENCED A LOSS OF ENGINE POWER IN THE TAKEOFF INITIAL CLIMB, ABOUT 450 FEET AGL, AND THE PILOT AUTOROTATED TO A HARD LANDING ON A CITY STREET.  A WITNESS WHO SAW THE HELICOPTER HOVERING BEFORE TAKEOFF SAID THAT THE ENGINE 'MISSED' TWICE BEFORE THE HELICOPTER TOOK OFF.  AFTER THE HELICOPTER TOOK OFF AND WAS ABOUT 80 TO 90 FEET AGL, HE HEARD THE ENGINE MAKE A 'SPUTTERING' OR 'POPPING' NOISE.  THIS FLIGHT WAS THE FIRST TEST FLIGHT AFTER BUILDING THE HELICOPTER AND THE PILOT HAD COMPLETED 4.3 HOURS OF ENGINE RUN-UPS AND HOVER TIME.  EXAMINATION OF THE ENGINE FOUND THAT THE NO. 3 CYLINDER INTAKE VALVE STEM CAP WAS DAMAGED AND THE ROCKER ARM WAS LOOSE.  THE VALVE LASH CLEARANCES ON THE OTHER THREE CYLINDERS WERE FOUND TO BE FROM 0.006 TO 0.022 INCHES GREATER THAN THE MANUFACTURER'S SPECIFICATIONS.  NO OTHER DAMAGE WAS NOTED TO THE ENGINE OR VALVE TRAIN.  THE NO. 3 CYLINDER INTAKE VALVE STEM CAP WAS REPLACED AND THE OTHER VALVE CLEA                                                 RANCES SET TO THE PROPER 0.004-INCH SPECIFICATION. THE ENGINE WAS THEN INSTALLED IN A TEST CELL AND PERFORMED NORMALLY DURING ALL OPERATIONAL TESTS.  THE ROTORWAY ENGINE MAUAL INSTRUCTS OWNERS TO MEASURE AND ADJUST THE VALVE LASH, AND STATES, 'IF ANY ADJUSTMENT IS NECESSARY AT ONE HOUR, VALVE ADJUSTMENT SHOULD BE REPEATED HOURLY UNTIL THE LASH STABILIZES.'  THE PILOT REPORTED THAT HE HAD MADE A TOTAL OF FOUR ADJUSTMENTS DURING THE FIRST INSPECTION, BUT AFTER THAT, ALL MEASUREMENTS HAD BEEN WITHIN THE MANUFACTURER'S SPECIFICATIONS.

## The NTSB's investigation of this event (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 LAX99LA236](https://openairdocs.org/ntsb/LAX99LA236), Jun 25, 1999: Miller Rotorway Exec 162F (N112WM), Pacoima, CA, substantial damage. Probable cause: The pilot's improper valve adjustments and failure to follow the manufacturer's instructions, which resulted in a loose number 3 cylinder rocker arm and a loss of engine power.

From the FAA Accident/Incident Data System. Reports are matched to registry aircraft by N-number and event date, checked against the reported make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. For accidents, the NTSB's own investigation is the fuller record.

---
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.