Individually Owned: 151,845
Corporate Owned: 143,699
Kona International Airport
Aircraft Accident/Incident Report
Kailua-Kona, Hawaii 96745
Saturday, April 23, 2005 17:00 HST
NTSB Narrative Summary Released at Completion of Accident
The helicopter was ditched in the ocean after a complete loss of engine power. Post-accident examination of the engine revealed that the #3 cylinder's exhaust valve had failed. Because of mechanical damage and oxidation to the fracture surfaces, the specific cause of the exhaust valve failure could not be precisely determined. However, it was most likely related to overheating and non-uniform seating loads due to the severe wear and bell-mouthing of the valve guide. The bent pushrods found during the examination also indicated some valve sticking in the guides prior to failure that caused excessive loads in the pushrods. Valve stems and guides were normal wear items. Mutual wear increased the stem to guide clearances and exhaust valves, particularly the sodium filled valves utilized in the accident engine, rely on proper clearance to the guide to maintain good heat transfer properties. The most likely scenario for this failure was that the valve-to-guide clearance became so great as to impede heat transfer from the valve to the head through the guide. The valve then overheated as indicated by the decreased stem hardness and radial head cracks found during the metallurgical examination. Off center valve closure loads, due to the bell mouthing, then fractured the overheated and lower strength valve head. In May 1992, the engine manufacturer issued a service bulletin (SB) recommending engine inspections to determine the wear condition of exhaust valve and guides. The SB details procedures to assess the wear on the engine by wobbling the valve in the head. The SB recommended performing this inspection every 300 hours on helicopter engines. Engine logbooks only showed that the SB was complied with twice, once in January 2005, at 1,921.8 hours, and the last time in March 2005, at 2,204 hours total time. The last inspection was only 133.3 hours prior to the accident. The engine manufacturer reported that if performed properly this inspection method would have been successful in detecting excess valve wear. The presence of extensive lead deposits on the valve stem and in the valve spring keeper groove indicated that stem to guide clearances were relatively large allowing the passage of combustion products for an extended period of time. This suggests that the SB inspections were not performed properly.
NTSB Probable Cause Narrative
a total loss of engine power due to the failure of the engine's #3 exhaust valve due to an excessive valve guide clearance. Contributing to the accident was the failure of maintenance personnel to adequately check the valve guide clearance during the last valve guide inspection.
Event Information
| Type of Event | Accident |
| Event Date | 4/23/2005 |
| Event Day of the Week | Saturday |
| Time of Event | 1700 |
| Event Time Zone | Hawaii Standard Time |
| Event City | Kailua-Kona |
| Event State | HAWAII |
| Event Country | -- |
| Zipcode of the event site | 96745 |
| Event Date Year | 2005 |
| Event Date Month | 4 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 194310N |
| Event Location Longitude | 1560330W |
| Event Location Airport | Kona International |
| Event Location Nearest Airport ID | KOA |
| Indicates whether the acc/inc occurred off or on an airport | Off Airport/Airstrip |
| Distance from airport in statute miles | 3 |
| Degrees magnetic from airport | -- |
| Airport Elevation | -- |
| Weather Briefing Completeness | -- |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 1653 Hawaii Standard Time |
| Direction of event from weather observation facility (degrees) | -- |
| Weather Observation Facility ID | PHKO |
| Elevation of weather observation facility | -- |
| Distance of event from weather observation facility (units?) | -- |
| Time Zone of the weather observation | HST |
| Lighting Conditions | Day |
| Lowest Ceiling Height | -- |
| Lowest Non-Ceiling Height | 7000 |
| Sky/Lowest/Cloud Conditions | Scattered |
| Sky Condition for Lowest Ceiling | None |
| Visibility Runway Visual Range (Feet) | -- |
| Visibility Runway Visual Value (Statute Miles) | -- |
| Visibility (Statute Miles) | 10 |
| Air Temperature at event time (in degrees celsius) | 27 |
| Dew Point at event time (in degress fahrenheit) | 18 |
| Wind Direction (degrees magnetic) | 220 |
| Variable Wind Indicator | Wind direction could be determined |
| Wind Speed (knots) | 9 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 30.01 |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | -- |
| METAR weather report | -- |
| Event Highest Injury | None |
| On Ground, Fatal Injuries | -- |
| On Ground, Minor Injuries | -- |
| On Ground, Serious Injuries | -- |
| Injury Total Fatal | -- |
| Injury Total Minor | -- |
| Injury Total None | 2 |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 20174 |
| NTSB Notification Source | FAA |
| NTSB Notification Date | Apr 23 2005 12:00AM |
| NTSB Notification Time | 1820 |
| Fiche Number and/or location -used to find docket information | DMS |
| Date of most recent change to record | Aug 29 2006 3:49PM |
| User who most recently changed record | NTSB\JOHB |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | Honolulu, HI FSDO |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N8406J |
| NTSB Number | LAX05LA146 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 91: General Aviation |
| Type of Flight Plan filed | None |
| Flight plan Was Activated? | No |
| Damage | Substantial |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | Robinson Helicopter Company |
| Aircraft Model | R22A |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 350 |
| Certified Max Gross Weight | 1370 |
| Aircraft Category | Helicopter |
| Aircraft Registration Class | -- |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | -- |
| Cabin Crew Seats | -- |
| Passenger Seats | -- |
| Total number of seats on the aircraft | 2 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | 100 Hour |
| Date of Last Inspection | Apr 1 2005 12:00AM |
| Airframe hours since last inspection | -- |
| Airframe Hours | 2338 |
| ELT Installed | No |
| ELT Activated | -- |
| ELT Aided Location of Event Site | -- |
| ELT Type | -- |
| Aircraft Owner Name | Hawaii Pacific Aviation, Inc. |
| Aircraft Owner Street Address | 73-310 U'u Street |
| Aircraft Owner City | Kailua-Kona |
| Aircraft Owner State | HI |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 96740 |
| Operator is an individual? | No |
| Operator Name | -- |
| Operator Same as Owner? | Yes |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | Yes |
| Operator Street Address | -- |
| Operator City | -- |
| Operator State | -- |
| Operator Country | -- |
| Operator Zip code | -- |
| Operator Code | -- |
| Owner has at least one certificate | None |
| Other Operator of large aircraft? | -- |
| Certified for Part 133 or 137 Operation | -- |
| Operator Certificate Number | -- |
| Indicates whether an air carrier operation was scheduled or not | -- |
| Indicates Domestic or International Flight | -- |
| Operator carrying Pax/Cargo/Mail | -- |
| Type of Flying (Per_Bus / Primary) | Instructional |
| Second Pilot on Board | Yes |
| Departure Point Same as Event | Yes |
| Departure Airport Code | KOA |
| Departure City | Kailua-Kona |
| Departure State | HI |
| Departure Country | USA |
| Departure Time | 1650 |
| Departure Time Zone | HST |
| Destination Same as Local Flt | dest & departure same, accident can occur anywhere |
| Destination Airport Code | -- |
| Destination City | -- |
| Destination State | -- |
| Destination Country | -- |
| Specific Phase of Flight | Climb - to cruise |
| Report sent to ICAO? | No |
| Evacuation occurred | Yes |
| Date of most recent change to record | Jun 2 2006 6:04PM |
| User who most recently changed record | COOS |
| Since inspection or accident | Time of Accident |
| Event Location Runway Number and Location | NA |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |