The first passenger attendants flew not on aeroplanes but on airships, before World War I. By the 1920s, boys were being employed as stewards on the small-cabined airliners of the time. By the late 1920s, adult stewards were serving meals, and by the early 1930s, women were being employed as ‘air hostesses’. However, the prime function of cabin crew is safety, not service. Cabin crew are trained in aircraft evacuation, effective communication and leadership, first aid and conflict resolution. Studies have identified effective cabin crew as important in ensuring the safe and swift evacuation of an aircraft.
Aircraft type certificates have been around since the 1920s. In essence they are a set of rules and standards that any aircraft design must meet. Changes to the aircraft’s design, such as different engines or floats, are covered by a supplementary type certificate. Certification standards also apply to aircraft equipment, such as avionics, to ensure that only safe and reliable technologies are used. A type certificate is valid for as long as an organisation, be it the original manufacturer or another business, is willing to support the aircraft with spares and maintenance in/safety information.
Behaving predictably near an airfield—having standardised circuit procedures—is one of the foundations of safe VFR flying. By standardising arrivals and approaches there is less potential for aircraft to ‘conflict’ with one another.
Early aviators depended on their clothing—to keep them warm, dry and, in some aircraft types, clean. It’s almost the definition of progress in civil aviation that passengers and crew on the Concorde were able to fly faster than a bullet in the same clothes they wore in the airport, but clothing still has a safety role in military and sports aviation. Military fast jet pilots use flame and G-resistant suits. In offshore helicopter transport, passengers require immersion suits, while commercial agricultural and helicopter pilots routinely wear fire-resistant clothing, often discreetly tailored so as not to alarm passengers.
The Boeing B-17 nearly didn’t get made after its prototype, the Model 299, crashed on take off in 1935. It was discovered that the crew had forgotten to disengage a gust lock. Newspaper reports of the time described the 299 as ‘too much airplane for one man to fly’, but the solution was simple—checklists. Four were developed for the B-17. By supporting (but never eliminating) human memory, checklists improve consistency and safety in flight and maintenance operations. The checklist, one of aviation’s greatest contributions to safety, has recently spread to areas such as surgery and software engineering.
An aircraft should be made out of stuff that is light, strong and durable. That’s a tall order for any material, and one that carbon-fibre composites come the closest to fulfilling. In principle, carbon-fibre composites are the same as a mud brick reinforced with straw. The two materials together are stronger than they are separately. In theory, composites have the fundamental advantage of immunity from the fatigue and corrosion that affects all metals. In practice, you require stringent and expensive quality control to make composites live up to their promise—like everything in aviation, they are not cheap.
Crew resource management
Crew resource management (CRM) is the effective use of all available resources for flight crew to ensure a safe and efficient operation, with fewer errors and less stress. CRM was made possible by two technologies. The introduction of flight data recorders (FDRs) and cockpit voice recorders (CVRs) revealed that many accidents did not result from a malfunction of the aircraft or from the crew’s lack of aircraft-handling skills or technical knowledge. Instead crews were responding inadequately; not communicating between themselves and losing situational awareness. This was how highly qualified and experienced crews flew an almost new Lockheed L-1011 Tristar into a swamp in 1972; and crashed a Douglas DC-8 in 1978 after running out of fuel, while attending to a blown gear-indicator bulb.
The other enabling technology was flight simulators, which allowed crew-cooperation scenarios to be practised. CRM is about developing the cognitive and interpersonal skills needed to manage a flight safely.
The best way to fly safely is not to crash—no argument there. But it is also true that aircraft will crash from time to time, despite the best efforts of everyone in aviation. Designing aircraft that can minimise the injury caused in a crash should be a logical response. Recent developments in air transport aircraft, such as stronger 16G seats, better overhead luggage bins that are less likely to spill their contents, more widespread use of fire-resistant materials, and larger emergency exits, have produced some impressive results. Several recent airliner crashes have been fatality-free despite the aircraft being destroyed or written off. Recent general aviation designs, using carbon-fibre composite construction and seatbelt-mounted airbags, show promise in this area too.
Flight data recorders and cockpit voice recorders mean that any accident on an aircraft equipped with them is also an opportunity to learn. Introduced in the early 1960s, these orange-painted devices have progressed from magnetic tape recording to digital technology.
Most impressive are the toughness standards CVRs and FDRs have to meet. The include resistance to 1100 degrees Celsius for one hour and 260 degrees for 10 hours, water resistance to a depth of 6000 metres and impact resistance of 3400g for 6.5 milliseconds.
Dangerous goods control
The danger in taking flammable, volatile cargo on aircraft has been illustrated too many times. South African Airways Flight 295 was lost in the Indian Ocean in November 1987 after an in-flight fire in the cargo hold. The holds of most airliners are now equipped with automated halon fire-extinguishing systems to combat any cargo or baggage fire. In May 1996, ValuJet Airlines Flight 592 crashed into the Florida Everglades a few minutes after take off, when a fire broke out in the forward cargo hold. All 110 aboard were killed. These tragedies also refocused attention on screening to prevent dangerous goods from being carried on aircraft. Dangerous goods control is an ever-changing game. New technologies bring new types of dangerous goods, with lithium-ion batteries being a recent example.