One of the earliest implementations of advanced digital technology, after the introduction of the autopilot and auto-throttles, was the flight management system. This consists of a computer with stored or crew-entered navigational fixes that can be linked to the auto-pilot. The key pad being selected is an early flight management system fitted to a Boeing 747-200.
Fly-by-wire (as fitted to the Airbus A340, for example) has effectively ‘uncoupled’ the direct link between pilot and flying controls, and together with a digital flight control system allows aircraft to be flown that are inherently unstable. Among the advantages of these factors are that the aircraft can be lighter, hence cheaper to build and operate, leading to lower fares and environmental impact. It also allows the flight characteristics to be ‘programmed’, which relieves the pilot workload and ensures that the flight envelope cannot be exceeded.
Introduction of the Boeing 767 heralded the first widespread airline use of electronic flight instrumentation systems. Early EFIS screens consisted of small CRTs which displayed the navigational plan, but more recent EFIS systems utilise LCDs.
There may come a day when all the primary flight information will be displayed on the head-up display, thus freeing up the main instrument panel to display such things as weather information and instrument approach information. The business jet community is also working on synthetic vision systems, essentially radar, which can see through fog and project the generated image of the runway on the HUD. Among the business jets currently offered with head-up display is the Gulfstream V.
Auto-throttles are normally used only in flight and for landing, but Bombardier has introduced an enhanced auto-throttle on its Challenger 604 which can also be used during take-off. The auto-throttle is part of the new Bombardier PrecisionPlus avionics upgrade and made its international debut at FIDAE 2002.
To reduce drag, the size of the MD-11’s tailplane was reduced to approximately 59% of that of its predecessor, the DC-10 and the resulting reduction in longitudinal stability was alleviated by incorporating a pitch stability augmentation system.
Intuitively, more crew members increase the margin of safety: though this may only be true if all crew members have regular hands-on experience. Analysis of an aircraft which almost crashed following an engine failure on take-off found that the First Officer made incorrect control inputs and postulated that this may have been due to the fact that the individual in question had been flying the relief category for so long that he/she had not made an actual (non-simulator) take-off in a 747 in almost three years. Perhaps this incident indicates that adding people is no longer analogous with increasing safety.