Individually Owned: 150,657
Corporate Owned: 137,281
Aircraft Accident/Incident Report
Prescott, Arizona 86301
Wednesday, October 10, 2007 10:14 MST
NTSB Narrative Summary Released at Completion of Accident
While in cruise flight, the engine had a sudden partial loss of power and made "clanging" noises. Although the engine continued to operate at a maximum of 900-1,100 revolutions per minute (rpm), insufficient power was available to maintain altitude. The pilot contacted the tower of a nearby airport, but determined that he would not be able to reach the runway. Due to power lines and a blind curve on a paved road, the pilot opted to land adjacent to the road. The airplane impacted a ditch and came to rest inverted. The engine had been overhauled 2.0 flight hours before the accident. A field overhaul had been performed on the engine due to a bent pushrod, stuck valve, and broken lifter for the number 3 cylinder. During the field overhaul, all four of the rocker arms had been magnetic particle inspected. Examination of the engine revealed that the number 3 cylinder exhaust rocker arm had separated into two pieces. A metallurgical examination was performed on the rocker arms by a Safety Board metallurgist. The number 3 exhaust rocker arm had fractured around the central pivot hole due to fatigue. The fatigue originated at the outer surface of the oil hole. The corners of the hole were sharp and had not been deburred, which increases the likelihood of fatigue cracking. The outer surface of the fatigued area was 0.31 inches long on the left side of the oil hole, and 0.21 inches long on the right side. The fractured exhaust rocker arm had been magnetic particle inspected for cracks during the field overhaul. The Safety Board metallurgist also noted staining on the cracks from the solution used during the magnetic particle inspection. Based on the staining, the cracks would have been detectable in size (about 0.2 inches) at the time of the inspection.
NTSB Probable Cause Narrative
The failure of maintenance personnel to detect fatigue cracks in the number 3 exhaust rocker arm, which lead to a partial loss of engine power.
Event Information
| Type of Event | Accident |
| Event Date | 10/10/2007 |
| Event Day of the Week | Wednesday |
| Time of Event | 1014 |
| Event Time Zone | Mountain Standard Time |
| Event City | Prescott |
| Event State | ARIZONA |
| Event Country | -- |
| Zipcode of the event site | 86301 |
| Event Date Year | 2007 |
| Event Date Month | 10 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 343916N |
| Event Location Longitude | 1122510W |
| Event Location Airport | -- |
| Event Location Nearest Airport ID | -- |
| Indicates whether the acc/inc occurred off or on an airport | Off Airport/Airstrip |
| Distance from airport in statute miles | -- |
| Degrees magnetic from airport | -- |
| Airport Elevation | -- |
| Weather Briefing Completeness | -- |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 953 Mountain Standard Time |
| Direction of event from weather observation facility (degrees) | 90 |
| Weather Observation Facility ID | PRC |
| Elevation of weather observation facility | 5045 |
| Distance of event from weather observation facility (units?) | 9 |
| Time Zone of the weather observation | MST |
| Lighting Conditions | Day |
| Lowest Ceiling Height | -- |
| Lowest Non-Ceiling Height | -- |
| Sky/Lowest/Cloud Conditions | Clear |
| 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) | 23 |
| Dew Point at event time (in degress fahrenheit) | -6 |
| Wind Direction (degrees magnetic) | 140 |
| Variable Wind Indicator | Wind direction could be determined |
| Wind Speed (knots) | 6 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 30.16 |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | -- |
| METAR weather report | -- |
| Event Highest Injury | Minor |
| On Ground, Fatal Injuries | -- |
| On Ground, Minor Injuries | -- |
| On Ground, Serious Injuries | -- |
| Injury Total Fatal | -- |
| Injury Total Minor | 1 |
| Injury Total None | -- |
| Injury Total Serious | -- |
| Injury Total All | 1 |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 24415 |
| NTSB Notification Source | FAA |
| NTSB Notification Date | Oct 10 2007 12:00AM |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | -- |
| Date of most recent change to record | Oct 10 2008 12:30PM |
| User who most recently changed record | coos |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | Scottsdale FSDO |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N9897G |
| NTSB Number | LAX08LA009 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 91: General Aviation |
| Type of Flight Plan filed | None |
| Flight plan Was Activated? | -- |
| Damage | Substantial |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | Cessna |
| Aircraft Model | 172L |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 17259797 |
| Certified Max Gross Weight | 2300 |
| Aircraft Category | Airplane |
| Aircraft Registration Class | -- |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | -- |
| Cabin Crew Seats | -- |
| Passenger Seats | -- |
| Total number of seats on the aircraft | 4 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | Annual |
| Date of Last Inspection | Oct 1 2007 12:00AM |
| Airframe hours since last inspection | 2 |
| Airframe Hours | 3670 |
| ELT Installed | Yes |
| ELT Activated | No |
| ELT Aided Location of Event Site | No |
| ELT Type | -- |
| Aircraft Owner Name | Gary E. Lewis |
| Aircraft Owner Street Address | -- |
| Aircraft Owner City | Prescott |
| Aircraft Owner State | AZ |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 86305 |
| Operator is an individual? | Yes |
| 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) | Personal |
| Second Pilot on Board | No |
| Departure Point Same as Event | No |
| Departure Airport Code | DVT |
| Departure City | Deer Valley |
| Departure State | AZ |
| Departure Country | USA |
| Departure Time | 900 |
| Departure Time Zone | MST |
| Destination Same as Local Flt | -- |
| Destination Airport Code | PRC |
| Destination City | Prescott |
| Destination State | AZ |
| Destination Country | USA |
| Specific Phase of Flight | Cruise |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | -- |
| User who most recently changed record | -- |
| Since inspection or accident | Time of Accident |
| Event Location Runway Number and Location | N/A |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |