By Jack Drake | August 1, 2008
A detailed analysis of flight training accidents revealed errors for pilots, both experienced and new, to avoid.
During the past two years, I have had the privilege and responsibility of co-chairing the accident-analysis working group of the International Helicopter Safety Team. That team aims to slash the rate of helicopter accidents 80 percent by 2016, and a thorough analysis of the causes of such accidents is the foundation of its efforts.
The Joint Helicopter Safety Analysis Team (JHSAT), as our working group is known, started with accidents in the U.S. National Transportation Safety Board database for the year 2000. There were two key reasons: that year’s data was considered complete and the accidents were no longer tied up in litigation (which otherwise might have prevented some team members from participating in the analysis).
The experience of analyzing those accidents was eye-opening. When we take a look at the preliminary data on more recent accidents (those from 2007), the experience also becomes frustrating. There is little improvement evident during the intervening years.
We divided the accidents into mission groups. More accidents occurred in the "instructional" group than any other single group. (The groups with the next highest accident counts were "personal flying" and "aerial application.") That may not be surprising, but some of our other findings were. For instance, instructional accidents have been increasing in recent years while the overall number of helicopter accidents has been declining. Also, most of the accidents occurred when a certificated flight instructor (CFI) was in the cockpit, and the average flight experience of the CFIs involved in the accidents was quite high.
The desire of everyone on the analysis team was to delve deeper into the causes of accidents than most past reports allowed. (Analysis team members included representatives of Air Methods, American Eurocopter, Bell Helicopter, Bristow Group, the FAA, NASA, Rolls-Royce, Schweizer Aircraft, Sikorsky Aircraft, Silver State Helicopters and Turbomeca. My co-chair was Mark Liptak of the FAA’s Engine and Propeller Directorate. I represented the Helicopter Assn International. Hopefully, this article will prompt many of you to look more critically at your operations to see how they compare with the accident data unearthed by our analysis.
Of the 197 accidents from 2000, 37 (or nearly 19 percent) involved instructional flights.
As you might imagine, the experience level of the pilots involved varied widely. For this reason, we divided the accidents into three groups. The first involved student pilots on solo flights. The second was made up of training flights with an instructor with fewer than 1,000 hr as a CFI. The last covered training flights with higher-time CFI (or CFIs for whom time was not reported).
There were 10 student solo accidents; five occurred in what are considered low rotor-inertia helicopters. All were conducted during the day and in visual meteorological conditions (VMC). Except for one involving a relatively experienced airplane-rated pilot, the accidents involved students with an average of 68 total flight hours and 43 rotorcraft hours. Pilot-in-command time in the aircraft type involved in the accident averaged 4.8 hr.
Eight accidents involved loss of control at low altitude. One was an inadvertent takeoff during a ground magneto check and one a loss of control while trying to land on a trailer. One followed aggressive use of controls, another from failure to maintain rotor rpm. Of the remaining two, one involved tail-rotor failure on the ground and the other involved the helicopter’s use to escape police.
In the second group, involving CFIs with 1,000 hr or less, there were 12 accidents. Ten occurred in low rotor-inertia helicopters and 10 in daylight VMC. (One was at night, and no lighting conditions reported for the other.)
Total flight time for the CFIs involved was 1,734 hr, 764 of them in helicopters and 588 in the aircraft type involved in the accident. Seven of the 12 CFIs had fewer than 1,000 hr total time, and five had fewer than 500 hr in helicopters. The 12 averaged 404 CFI hours. Three said they had fewer than 50 hr instructing in the type involved in the accident.
The accidents in this group included two CFI-demonstrated full autorotations that resulted in noseovers, one in which the CFI had a dynamic rollover on takeoff and one in which the CFI pressured himself to fly, encountered instrument meteorological conditions and crashed. Seven of the 12 occurred during practice autorotations. One happened when a student lost control in a hover, one during a running takeoff on snow, and another while practicing landings.
Most common in these accidents were the use of low rotor-inertia helicopters and late or inadequate CFI intervention after the student allowed rotor rpm to drop or improperly operated flight controls.
There were 15 accidents in the group involving the highest-time CFIs. They involved a wider variety of aircraft (six single-engine turbine, one twin turbine and eight light piston helicopters) and frequently occurred during mission qualification and check rides. All 15 occurred in daylight VMC. The pilots-in-command involved reported an average of 9,784 hr total flight time, 8,106 in rotorcraft and 3,041 in the type involved in the accident. The hours were skewed by eight pilots who reported an average of 14,841 hr total time. Three of the pilots reported 200 hr or less instructor time in the type involved.
Four accidents happened during instructional flights with a student on board. Three occurred during differences or emergency training and three during CFI training. Two occurred during Part 135 or company flight checks. One each occurred during training of a commercially rated student, during an evaluation flight and during factory flight training by an OEM. In 11 of the 15 accidents, the NTSB cited inadequate intervention or supervision by the CFI after an error by the "student" as a cause or factor.
Preliminary NTSB data on 2007 accidents indicates the numbers were up (55 instructional accidents compared to 37 in 2000). One large operator (no longer in business) had 13 accidents involving 14 aircraft. Another large operator had none, proving that accidents are not inevitable. They can be prevented by good training, sound management and proactive safety programs. Twelve of the 2007 accidents involved solo students, and 39 were dual-instructional flights. Three solo accidents were secondary to power losses; the others resulted from loss of control. Most of the dual-instruction accidents were the result of CFI errors while demonstrating maneuvers or failure to intervene appropriately following student errors. Also, 19 occurred secondary to practice autorotations, none of which were concluded as planned in a power recovery.
Our team identified common problems, or links that led to each of the 2000 accidents and made preliminary recommendations on how to eliminate or mitigate them. A separate group, the Joint Helicopter Safety Implementation Team, will identify which recommendations are most promising and how they can best be implemented. Some of our recommendations that might be most useful include: promoting a culture of safety and regulatory compliance that includes non-punitive reporting and open communication; not tolerating deliberate risk-taking; and proactively using safety information to continually raise standards and reduce accident risk. We also called for identifying risks associated with instructional flight operations and providing training in operational risk assessment of that mission; establishing, overseeing and requiring adherence to company operational standards; and monitoring employee performance and providing training to ensure it stays at a high level. Further, we recommended focused training for CFIs to address best practices for preflight preparation, communication, transfer-of-control protocols, and risk reduction when flying with students and to reduce risk of accidents involving autorotations, loss of tail rotor effectiveness and dynamic rollover.