Page 42 - Twin and Turbine June 2017

Twin Proficiency
by Thomas P. Turner
Recurrent Reality Check
Twin and Turbine’s editor Dianne White posed an intriguing series of questions to me:
“When working on our multi-engine rating, we spend most our time practicing engine-out technique, which is critical. But is engine failure what kills pilots and their passengers? Or are they more the result of flying into stuff – weather and terrain? When we do recurrent training we once again go through single-engine work, but what other scenario-based training could we be doing based on what is really killing people? If you were designing a recurrent training session for multi- engine pilots, what would it include?”
Take a moment and think about your response to those questions. Then read on, and using real data I’ll answer her questions from my viewpoint as a multiengine instructor for nearly 30 years, in simulators and in the airplane itself.
The Multi-Engine Record
Most authoritative studies of general aviation accident causes rightly quote AOPA Air Safety Institute’s annual Nall Report. This report, available on the AOPA website, relates and comments upon trends in light plane crashes by careful review of the most recent NTSB Probable Cause findings. The Nall Report, however, does not break accident causation down by airplane class. It does have some statistical breakdowns of single- and multi-engine crash scenarios, but it does not provide separate studies for single-engine and multi-engine airplanes. As one researcher put it, AOPA “chose[s] to focus on accident types rather than aircraft types.”
To answer the first of our questions – is engine failure what kills pilots and their passengers? Or are more the result of flying into stuff such as weather and terrain? – we need to go deeper into the data. Further analysis of 10 years of NTSB data (2005-2014) reveals there were 365 fatal multi-engine piston and light turboprop crashes during that period (averaging 36.5 per year or one every 10 days for a decade). The top five cause scenarios are listed in rank order below.
Rank Order
Cause/Scenario
Total Crashes
% of Total Fatal Crashes
1
Loss of control: Unexplained power loss
41
11.2%
2
Loss of control during/immediately after takeoff
36
9.6%
3
Loss of Control or CFIT: IFR in IMC
30
8.2%
4
Attempted visual flight in IMC
29
7.9%
5 (tie)
Fuel mismanagement
23
6.3%
5 (tie)
Stall during approach/traffic pattern
22
6.3%
These top five causes account for 49.5 percent of the fatal events, meaning that fatal accidents are distributed across a small number each of a wide variety of individual scenarios.
Looking at these numbers, it appears that if anything we need to be focusing more on engine- failure scenarios in recurrent multi-engine training. The trouble is, it is not safe to accurately practice the most critical engine failure in an airplane, and it is not accurate to safely practice them. The most critical
40 • TWIN & TURBINE
June 2017