Piper PA-34-200 accident near Westlake Villag, California, January 11, 2003
On January 11, 2003 at about 6:23 pm local time, a Piper PA-34-200, registered N56484, was destroyed in an accident near Westlake Villag, California. It was an instructional flight under general aviation rules (Part 91). 2 people were seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
a fatigue crack in the propeller hub due to the inadequate design location of the grease fitting and the chamfering process.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- January 11, 2003 · about 6:23 pm local time
- Place
- Westlake Villag, California · map
- Type
- Accident
- Injuries
- 2 people were seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Piper PA-34-200 · all PA-34-200s on the register
- Registration
- N56484 · no longer on the register · serial 34-7350338
- Damage
- Destroyed
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The airplane collided with ground obstacles during a forced landing when the pilots could not maintain altitude after one propeller blade and part of the propeller hub from the right engine separated in flight. The CFI and the student practiced two simulated engine-out maneuvers. The CFI was reaching for the mixture control for a third simulation when he heard a loud bang. The airplane yawed violently to the right and began to lose altitude. The CFI turned toward his home field, but was having difficulty maintaining altitude. He decided that he would not be able to make it to the airport, and would have to make an off field landing. He landed in the only clear spot that he could see, which was a cemetery. The airplane collided with monuments and a wood chip pile before coming to rest next to a mausoleum. The right propeller hub fractured and separated. Investigators did not recover one blade and the corresponding part of the hub. The hub fractured as a result of fatigue cracking emanating from one of the grease-fitting holes. The fatigue cracking originated in the area of the grease-fitting threads closest to the interior surface of the hub, at the intersection between the grease-fitting hole and the chamfer. No material or manufacturing defect was found that could be identified as the source of the fatigue cracking. The fatigue cracking originated just outside the thread remnants of the grease fitting hole that were plastically deformed during a chamfering process. The grease fitting was located in a region where the wall of the hub was approximately at its thinnest, and where there was a slight change in the profile along the axis of the propeller. These geometrical factors would have led to high stresses at the edges of the hole. Chamfers were retrofitted to the grease-fitting holes by the manufacturer at both the interior and exterior surfaces of the hub in response to fatigue fractures that occurred in three-bladed propellers. This accident was the first occurrence of fatigue emanating from a grease-fitting hole for a two-bladed propeller. The chamfering was apparently introduced in an effort to smooth the stress distribution around the grease-fitting holes. The chamfer at the interior surface should have removed the stress concentration associated with the change in wall profile, but would also have decreased the amount of material in the wall, leading to higher stresses overall. The stress concentration associated with the grease-fitting hole and the chamfer, coupled with the location in a position where the hub wall was very thin, were likely sufficient to initiate fatigue cracking in this case. In more recently manufactured hubs, the grease-fitting holes have been relocated to positions where the hub wall is much thicker.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
Flight instructor
- Certificate: flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instrument: airplane
- Flight time: 3,500 hours in all
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: rgt
- Injury: serious injuries
Dual student
- Certificate: private
- Ratings: single-engine land
- Flight time: 145 hours in all; 6 in this make and model; 9 in the last 90 days; 7 in the last 30 days; 80 as pilot in command
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: left
- Injury: serious injuries
The aircraft
- Last inspection: 100-hour inspection, November 29, 2002; 256 hours since
- Maximum gross weight: 4,200 lb
- Seats: 6
- Landing gear: retractable
- Engine 1: Lycoming IO-360-C1E6 (piston); 0 hours total
- Engine 2: Lycoming LIO-360-C1E6 (piston); 0 hours total
- Operator: The Aero Club
The flight
- Departed from: VNY Van Nuys CA at 5:45 pm
- Flight plan: none
- A second pilot was aboard
Weather at the time
- Light: daylight
- Visibility: 6 statute miles
- Sky: a few clouds at 600 ft
- Temperature: 52°F (11°C), dew point 46°F (8°C)
- Altimeter: 30.17 inHg
- Observation at 4:58 pm from VNY, 20 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 2 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Other NTSB records under N56484 the same tail number, which may have belonged to a different aircraft at the time
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.