There was not a single "crash" among the world's major carriers in the first half of 2001. The total number of fatal accidents among all sectors of commercial air transport was lower than at any time since 1984 when the number of flights was little more than half of what it is now. And the number of deaths through airline accidents was also at an all-time low.
Unfortunately, July has brought the first large passenger jet accident of the year, the crash of a Vladivostok Avia Tupolev Tu-154 (Flight International, 17-23 July). All 145 people on board were killed, so the second half of the year has not begun well.
The fatal accidents total for the first six months of 2001 was 13, and 114 people died in them - the lowest fatal casualties figure ever. In 1984, the previous best safety year, the equivalent numbers by the end of June were 12 fatal accidents and 134 fatalities.
To put this in context, the average number of fatal accidents in the first six months of each of the last 10 years was 20, and the number of deaths 445.
Proportionately, the first half of 2001 has seen only 65% of the last decade's average number of fatal accidents and a quarter of the fatalities. This half-year also compares well with 2000 at the same point, when there had been 19 fatal accidents and 552 fatalities. The overall good news is that, since 1994, the absolute trend in fatalities has been firmly downwards, and in fatal accident numbers is very slightly downwards. The three year moving average confirms this.
Thai Airways International has suffered the only fatal accident among scheduled international carriers. Although dramatic, it did not constitute a "crash" because Thai's Boeing 737-400 was on the stand and the passengers had not boarded. The explosion and the fire which gutted the aircraft resulted in one death among the cabin crew, but the other six crew members escaped. Thai investigators say that they are still keeping an open mind about the cause, but the US Federal Bureau of Investigation and the National Transportation Safety Board (NTSB) have dismissed the original theory of sabotage for lack of forensic evidence.
Meanwhile, the NTSB has drawn almost precise parallels with the conditions prevailing when, in 1990, a Philippine Airlines 737-300 experienced a centre-wing fuel tank explosion during pushback from the stand at Manila airport, Philippines, killing eight of the passengers. Boeing has reminded airlines to follow the procedures in the flight operations manual and not run fuel pumps in empty fuel tanks.
One of the most frightening events was the sidestick cross-wiring incident involving a Lufthansa Airbus A320. Had it not been for fast action by the co-pilot, the incident would have become a disaster in less than a second. This maintenance error was easy to make, because the electrical connections are not "Murphy-proofed". But an area of concern is that the fault was not detected in any of the post-maintenance and pre take-off checks which should have revealed it.
If, following the Simmons Airlines ATR-72 accident at Roselawn, Indiana, in November 1994, anyone doubted that modern turboprop commuter aircraft are sensitive to icing conditions, an incident this year confirmed it.
A Comair Embraer Brasilia and its crew were lucky to survive the dramatic manoeuvres of the aircraft when it began to pick up ice fast. According to the NTSB preliminary report, the crew effectively lost control, and the aircraft rolled left and right beyond 90í several times, before completing a full 360í roll and entering a 60° nose-down dive. The crew pulled 3.8g while recovering the aircraft.
It was loss of control in roll which led to the loss of 68 lives at Roselawn, and the NTSB wrote a damning report on the ATR72's sensitivity to icing. Its anti-icing systems have since been improved, but ATR at the time pointed out that the icing conditions in which the accident occurred were well outside limits which were made clear in the aircraft's flight manual, and serious icing had been forecast in the area.
Traditional approaches
Following the NTSB report, the US Federal Aviation Administration carried out extensive airborne icing tests on ATR series aircraft along with other commuter types. The FAA confirmed that aileron control on the modern commuters' supercritical sectioned wings was highly susceptible to icing, but that anti-icing systems powerful enough to proof the types against severe levels of icing were beyond the power output available from the engines. The conclusion was that the only safety measure available to crews was the traditional one: stay out of areas in which moderate to severe icing is forecast.
Although the safety figures for the first six months of 2001 are encouraging, a half-year is a short time in aviation, and the rest of the year has not started well. It would do no harm for the industry to glance back at what happened after 1984, which still stands as by far the safest full year for aviation safety. The next year, 1985, in contrast, was by far the worst year in its history.
Source: Flight International
