Serious incident Diamond DA 20C-1 N991CT,
ASN logo
ASN Wikibase Occurrence # 387555
This information is added by users of ASN. Neither ASN nor the Flight Safety Foundation are responsible for the completeness or correctness of this information. If you feel this information is incomplete or incorrect, you can submit corrected information.

Date:Saturday 1 July 2000
Time:13:00 LT
Type:Silhouette image of generic DV20 model; specific model in this crash may look slightly different    
Diamond DA 20C-1
Owner/operator:Smith And Barlow Enterprises
Registration: N991CT
MSN: C0091
Engine model:Continental IO-240
Fatalities:Fatalities: 0 / Occupants: 2
Aircraft damage: Minor
Category:Serious incident
Location:Spanish Fork, UT -   United States of America
Phase: En route
Departure airport:Provo, UT (KPVU)
Destination airport:Ephraim, UT (41U)
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
The pilot had just departed on a cross-country flight, and had climbed to 9,500 feet. He said that he began to feel a 'heavy vibration' in the aircraft, and immediately turned towards the closest runway. Soon thereafter the propeller separated from the airplane, and the pilot performed a forced landing without further incident. Postincident examination of the maintenance records indicated that the attachment bolts for the wooden propeller were last torqued 110 hours before the incident. The manufacturer of the propeller recommends that their wooden propellers be torque checked every 50 hours of flight. Examination revealed that the propeller attachment bolts showed signs of fatigue failure. There was also fretting damage on the propeller extension flange and bushing shanks. The above-mentioned signatures are suggestive of the studs being insufficiently torqued by the mechanic during assembly or periodic maintenance procedures not being followed, and subsequently becoming loose during propeller operation.

Probable Cause: The company maintenance personnel's inadequate torquing procedures of the propeller attachment bolts which resulted in the fatigue failure of the propeller attachment bolts and the in-flight separation of the propeller.

Accident investigation:
Investigating agency: NTSB
Report number: DEN00IA133
Status: Investigation completed
Duration: 9 months
Download report: Final report




Revision history:

03-May-2024 10:11 ASN Update Bot Added

Corrections or additions? ... Edit this accident description

The Aviation Safety Network is an exclusive service provided by:
Quick Links:

CONNECT WITH US: FSF on social media FSF Facebook FSF Twitter FSF Youtube FSF LinkedIn FSF Instagram

©2024 Flight Safety Foundation

1920 Ballenger Av, 4th Fl.
Alexandria, Virginia 22314