Bell 407 Accident History - what does it mean?
All,
I am in the process of getting qualified on the B407 and thought it might be instructive to review the accident history of this acft. What I found was not what I expected, and I am wondering if others can help me interpret/understand what I found. The surprising thing is that it seems that 46% of all accidents in the NTSB database are attributed to mechanical failure of some sort, and of these, 29% of all accidents are due to engine failure of some kind. This seems substantially higher than other helicopters I am familiar with. For example, the Enstrom 480 has experienced only one accident due to a mechanical failure over the same time frame, and even adjusted for fleet size, this is a substantially lower rate. (The single 480 accident attributed to mechanical failure was probably an outlier as it resulted from the failure of recently installed elastomeric MR dampers which later proved to be defective in design; none of the 480 accidents are attributed to engine failure.) The Robinson R22 and R44 are said to have around 5%-7% of accidents attributable to mechanical failure, although I havent been able to confirm this with hard data.
So, what is going on here? Is this an anomaly due to bad or insufficient data, a lack of understanding on my part, or is there something else at work?
(Detailed 407 data below)
BELL 407 ACCIDENT ANALYSIS*: <18 Apr 2009>
1 PILOT ERROR: 27 48%
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2 ENGINE FAILURE: 16 29%
2a TURBINE WHEELS: 5 9%
2b FADEC: 3 5%
2c OTHER: 8 14%
3 hangar BEARINGS: 3 5%
4 TR LOSS OF CONTROL: 2 4%
5 OTHER MECHANICAL: 5 9%
6 OTHER NON-MECHANICAL: 3 5%
ALL MECHANICAL CAUSES: 26 46%
*Based on NTSB website as of 18 Apr 2009 – 56 reported accidents since 1996
38% of all accidents (21) involved fatalities
7% of all accidents (4) involved mechnical failure and fatalities
15% of accidents due to mechanical causes involved fatalities (4)
Last edited by EN48; 19th Apr 2009 at 12:12.