January 1, 1993
By Bruce Landsberg
Sudden stops in moving vehicles are hard on the occupants, especially when the vehicle stops and the occupants don't. If, however, they both stop together, and if the cabin integrity is maintained, life generally goes on. Safety belts in aircraft have been around almost as long as aircraft themselves, but some real strides in occupant protection occurred when shoulder harnesses were introduced.
The importance of being completely and securely strapped in is pretty obvious. Seat belts and shoulder harnesses ensure that pilot and passengers don't get thrown around while the aircraft is in turbulent air or, in the case of aerobats, in unusual attitudes. In a worst-case scenario involving unscheduled contact with the ground, a fully belted crew should fare much better than one that is not strapped in.
Back in the early 1980s, the National Transportation Safety Board studied the supposed benefits of shoulder harnesses in general aviation aircraft. Not surprisingly, it found that preventing the second collision — pilot and passengers impacting the instrument panel or other aircraft structure — would cut fatalities by 20 percent and reduce serious injuries in survivable crashes by up to 88 percent.
Several accidents were specifically cited in the study with graphics that were, shall we say, persuasive. A Cessna 172 crashed on a gusty day while the pilot was attempting to land. The aircraft hit 35 degrees nose down and in a 90-degree right bank. The estimated speed was 60 to 75 knots. The attitude and speed made this accident borderline survivable. The NTSB decided that, had the pilot been wearing the available harness, his injuries would not have been fatal. The right-seat occupant also chose not to wear the harness and was seriously injured but could have gotten off with minor injuries.
Following fuel starvation, a Piper Warrior struck a tree with the right wing and contacted the ground 102 feet later, sliding to a stop in an additional 45 feet. The impact angle was estimated at 15 degrees, and the speed was less than 60 knots. This accident, from a deceleration viewpoint, was relatively gentle, yet the pilot and front seat passenger both sustained serious head injuries from snapping forward and hitting the instrument panel. The board's conclusion was that harnesses would have prevented two major headaches.
In analyzing accident injuries to 1,111 occupants, the NTSB concluded that 163 people might have been saved and 155 would have sustained lesser injuries by wearing shoulder belts. The results would have been even more dramatic if only survivable accidents had been studied.
During the summer of 1978, Federal Aviation Regulations were changed to require that shoulder harnesses be installed on the front seats of new-production light aircraft. I remember wondering what had taken our industry so long to adopt such an inexpensive step toward crashworthiness. Automobiles had been using them for years. The new regulations also insisted that pilots and front-seat passengers wear the harnesses during takeoff and landing, but the restraints could be stowed once enroute. It may be more comfortable to cruise unhooked, but it's not very smart. The NTSB study found, after talking with some seriously injured survivors of accidents, that in enroute emergencies, shoulder harnesses weren't donned because pilots were up to their armpits dealing with the emergencies. They forgot to put on the harnesses right when they were needed the most. Time is a critical factor in an emergency, and pilot work load is such that any task other than attending to the crisis and flying the aircraft is usually left undone.
The bulk of my flight time has been in aircraft old enough to vote. It used to be that I didn't give much thought to the probability and danger of a second collision in an accident. That is, until coming face- to-face, almost literally, with the instrument panel of a 1965 Mooney. The flight involved some moderate turbulence, and although I was belted in, the upper part of my body was tossed about — enough so that I was eying some of the knobs and switches close up. The installation of shoulder harnesses began to look like a worthwhile investment.
The factory was only too happy to oblige with a kit, complete with templates for the technician doing the installation. About $500 later, the crashworthiness of the Mooney had been significantly upgraded but not without some inconveniences. Aircraft haven't always been designed with a firmly strapped-in pilot in mind. The critical control that is usually out of reach and out of sight and, therefore, out of mind, is the fuel selector. In the Mooney, it was necessary to unstrap the harness, bend forward, switch tanks, and then restrap. At first, it seemed like a royal pain. But on reflection, the added safety of the shoulder harness was worth the inconvenience.
The NTSB study turned up some other interesting findings. In analyzing five specific accidents in which harnesses were worn by only one of the front-seat occupants, the injuries for the secured occupant were always less severe. That is a compelling argument. As with any passive safety device, a shoulder harness works only if it is used. At the time of the study, the NTSB estimated that harnesses were used only about 40 percent of the time. It sure would help our safety record for pilots to buckle up and to ask passengers to strap in and stay that way.
Cessna's Safety Enhancement Program offers retrofit harness kits for virtually every Cessna ever built and most of the other manufacturers do likewise. In a few cases, you may need to go to an aftermarket supplier, but it is worth the effort.
If we can cut the serious injury rate by 80 percent or more and also reduce the number of fatalities, then shoulder harnesses, low tech as they may be, should be high on every pilot's list of essential equipment. And they should be used all the time.
See also the index of "Safety Pilot" articles, organized by subject. Bruce Landsberg is executive director of the AOPA Air Safety Foundation.
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