DAVID LEARMOUNT / LONDON
Flight International's annual survey of business and general aviation accidents shows a worrying incidence of pilots losing control of their aircraft
Business and general aviation (GA) covers all operating environments, which may be why the spread of accident causes each year usually looks familiar. In 2001, however, there were many loss-of-control events, mirroring a change that has been taking place in airline accidents.
Last year there were five accidents to small twin-engined or turbine-powered aircraft in which the pilot lost control in the critical phase just before landing or just after take-off. This year started with another such crash in he UK, involving a Bombardier Challenger 604 at Birmingham Airport. All five people on board died when the aircraft dropped a wing just after take-off and cartwheeled when it hit the ground (Flight International, 15-21 January). Twelve months previously, in France, a pilot lost control of a Learjet 35A just before touchdown at Lyon Satolas Airport and died in the accident.
There were also 16 loss-of-control accidents last year that started in other flight phases. Because few have been fully investigated yet, it is not clear whether these were related to icing, pilot distraction or other causes. In eight of the cases, the aircraft were in bad weather, instrument meteorological conditions (IMC) or darkness, or all three, so pilot distraction or disorientation may at least have been contributory.
Looking at all of UK GA for 2001, the Civil Aviation Authority observes in its GA safety information leaflet (GASIL) that although bad weather and other factors reduced the amount of activity, the fatal accident numbers remained similar to those in 2000. GASIL notes that, while reports on these accidents are still awaited, "pilots have been losing control of their aircraft in good weather as well as bad. Control restrictions are not uncommon among the incident reports, but it is unusual to find them as major factors in accidents. Distraction, however, has always been a major killer and the priorities '1. Aviate, 2. Navigate, 3. Communicate' must always be remembered."
Robert Breiling, who heads his own US aviation safety consultancy, cautions against single-pilot operations by business-aircraft owners who do not fly often, particularly those who have upgraded from piston to the much greater performance of turbine power. He also draws attention to cargo operators that buy older Learjets or Cessna Citations, which he describes as "a real handful of aircraft" and fly them with "in-house trained" pilots.
In the commercial airline industry many recent loss-of-control events have been related to insufficient pilot knowledge of increasingly complex automated control systems, or flight management system confusion, but also to simpler causes such as disorientation. Loss of stick and rudder skills as a result of flying highly automated aircraft has been suggested as a possible cause for the increase in such events, but it is difficult to be certain of how much this could have contributed to an accident.
An accident on 29 March, 2001, has enabled the US National Transportation Safety Board to highlight a weakness in the system that it would like to see corrected. A two-pilot Gulfstream III air-taxi crew was flying a night VOR/DME approach to runway 15 at Pitkin County Airport, Aspen, Colorado. The visibility was poor in snow: two other business jets had already abandoned the approach and diverted, but the Gulfstream III hit a low hill 1.5km (1nm) from the runway end. The NTSB's verdict was that the crash would not have happened if the two pilots had co-operated. It was scathing in its criticism of their shortcomings as a crew. Among its observations in a letter to Federal Aviation Administration chief Jane Garvey, the NTSB concludes:
the captain did not give a briefing on the instrument- and missed-approach procedures or any other required information;
the crew did not make all the normal checklist instrument approach call-outs/crosschecks;
the captain did not include the first officer in the decision-making process;
the first officer did not question or challenge the captain or intervene "when he placed the aircraft in a potentially unsafe flying condition".
The NTSB is concerned that "Part 135 on-demand charter operators and other operators that conduct operations with aircraft requiring two or more pilots, do not need to meet the crew resource management [CRM] training requirements outlined for Part 135 commuter operators". The letter includes a formal recommendation to the FAA to change Part 135 rules "to require on-demand charter operators that conduct operations with aircraft requiring two or more pilots to establish an FAA-approved CRM training programme for their flightcrews". The CRM training, the agency makes clear, should be basically the same as that required for large airline operators.
Despite the weaknesses that continue to surface, figures drawn up for the US National Business Aircraft Association (NBAA) by Breiling show that fatal accidents for business aircraft in the years from 1996 to 2001 have levelled out at between 0.3 and 0.4 crashes per 100,000 flight hours, having improved rapidly during the first half of the decade. Separating Breiling's 2001 accident figures into corporate (professionally crewed) and business aircraft (which may be operated by a single pilot), corporate figures are as good as the major airline statistics at 0.108 total accidents per 100,000 flying hours, with a fatal rate of 0.031. Business aircraft, he says, achieve respectively 1.03 and 0.23.
The NBAA business aircraft statistics for the year 2001 compare favourably with the NTSB figures for Part 135 scheduled operations (small commuter aircraft) and Part 135 non-scheduled (on-demand air taxi services). The scheduled operators show a total accident rate of 1.407 accidents per 100,000 hours and a 0.402 rate for fatal accidents. Air taxis fared less well, with a total accident rate of 2.12 accidents per 100,000 flying hours and a fatal accident rate of 0.53. GA operations in 2001, according to the NTSB, show a total accident rate of 6.65 per 100,000 flying hours and a fatal accident rate of 1.22, a marginal improvement on the 2000 figures.
The Canadian Transportation Safety Board (CTSB) reports that there were 295 aviation accidents last year, excluding ultralights, and no accidents to major airlines. The numbers are down by 8% compared to 2000. The total accident rate reduced from 8.00 to 7.6 accidents per 100,000 flying hours, which the CTSB compares with a five-year average rate of 8.8. The accidents included one to a commuter airliner. The rest were in general aviation, including five involving air taxis.
Perhaps the most discouraging accident of 2001 was on 30 July at the Davidson Glacier, Alaska, which was a classic case of a pilot continuing into deteriorating weather despite all the available clues suggesting it was a bad idea. More encouraging was the event on 8 July, when a Pilatus PC-12 proved that an aircraft really can ditch safely. The occupants escaped in the raft that no-one ever expects to use.
Source: Flight International
