Single engine accident rate






August 2000


765 N.E. 35th Street, Suite B
Boca Raton, FL 33431
(561) 338-6900



At the request of Pilatus Business Aircraft Ltd., an analysis of U.S. General Aviation Aircraft Accidents was conducted to provide documented information to substantiate the reliability of a single turboprop powered aircraft.

Data provided has been compiled using the latest (published in Sept.1999) U.S. Federal Aviation Administration (FAA) and National Transportation Safety Board (NTSB) statistical data which has been released for the calendar year 1996, the latest available, and information extracted from their respective databases in Washington, DC.

Several different methods were used to identity powerplant reliability. They are:

o          Accidents involving power loss as a cause were analyzed for all major aircraft types

o          Power loss accidents were compared on an accident rate basis by accidents per 100,000 hours by major aircraft groups

o          Powerplant shutdowns per 1,000 hours of operation were reviewed for commercial operators required to report such data

o          Specific single turboprop powered aircraft accidents and accident rates were compared to that of a modern single reciprocating powered aircraft, other multi-engine turboprop aircraft and to selected multi-piston powered aircraft.


o          FAA compiled flight hours have been found to be extremely conservative in recent years particularly with turbojet and turboprop aircraft fleets. We have therefore used hours provided by the OEM's for single turboprop aircraft for the years 1992 through 1996.

o          As agricultural aircraft data is included in single engine and reciprocating turbo-prop, FAA/NTSB overall data, agricultural aircraft and flight hours have been deleted where necessary.

o          Flight hours have been extracted from "General Aviation and Air Taxi Activity Survey" reports published annually by the FAA and also reproduced by the General Aviation Manufacturers Association (GAMA). Excerpts of both reports are included in Section 10.



Powerplant Reliability Comparative Data - Five Year Average. 1992-1996

The following information is summarized from the contents of this report. Data is based on the latest information available from NTSB and FAA sources.

Accidents per 100,000 hours by major aircraft type, 5 year average 1992 - 1996
          Single engine reciprocating powered aircraft                      9.26
          Multi-engine reciprocating powered aircraft                       5.68
          Multi-engine turboprop powered aircraft                            4.34
          Single engine turboprop aircraft                                          1.46

2.          Percent of general aviation fixed wing aircraft accidents attributed to power loss -all causes-5 year average, 1992-1996
Single engine reciprocating powered aircraft                             33.5%
Multi-engine reciprocating powered aircraft                               27.6%
Multi-engine turboprop powered aircraft                                     8.0%
Single engine turboprop aircraft                                                      0%

3.          Percent of general aviation fixed wing aircraft accidents attributed to power loss due to mechanical/maintenance/design/manufacturer causes
Single engine reciprocating powered aircraft                             14.4%
Multi-engine reciprocating aircraft                                               8.9%
Multi-engine turboprop aircraft                                                   4.0%
Single engine turboprop aircraft                                                     0%

4.          Accidents per 100,000 hours due to power loss for mechanical/maintenance/ design/manufacturer (based on Commercial and Air Carrier operations data compiled by the FAA)
Single engine reciprocating powered aircraft                               1.33
Multi-engine reciprocating powered aircraft                                0.51
Multi-engine turboprop powered aircraft                                    0.17
Single engine turboprop aircraft excluding agricultural aircraft      0

5.          Powerplant shutdowns per 1,000 hours (Commercial/Air Carrier data) Average of selected powerplants, 1997
Reciprocating powerplant average                                              0.208
Turboprop powerplant average                                                  0.041


Summary/Findings (continued)

6.            Selected Aircraft Accident Analysis - Certification through 1999 - U.S. Fleet
                                                     Piper                   Cessna                Socata                 Pilatus
                                                  Malabu(sic)         Caravan            TBM 700             PC-12
Certification Date                          1983                    1984                    1988                  1994
U.S. Fleet Size                                749                      821                      74                     133
Accidents                                          79                        59                      5                         1
Fatal Accidents                                 25                        27                       1                         0
Accidents due powerplant
malfunction/failure                             14                         2                          0                        0*
Cumulative flight hours                 1,100,150          3,145,272               161,406             134,234
Accident rate/100,000 hrs.             7.18                    1.88                     3.10                     0.74
Fatal Acc. rate/100,000hrs.            2.27                    0.86                     0.62                       0
Power loss accident rate
per 100,000 hours                          1.27                  0.064                         0                        0

*1 non-U.S. registered PC-12 experienced an accident due to powerplant loss due to mechanical malfunction/failure


Based on the review and analysis of accident data involving multi and single reciprocating and turboprop powerplant malfunction/failure accidents and analysis of the various powerplant reliability data available, a single turboprop powered aircraft, with adequate backup systems provided in it's design, will be more reliable, involved in fewer powerplant malfunction/failure related accidents than that of single or multi reciprocating powered fixed wing aircraft and comparable to the reliability of a multi-turboprop powered aircraft.

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