Air safety
Criminal negligence
David W. Wragg
The Arab oil embargo has affected our lives in a number of ways — many of them painfully obvious, such as queuing for petrol and forgoing the trading stamps, paying a surcharge on a holiday booking or finding a business travel arrangement restricted by alterations to airline schedules. Even so, the oil embargo has been presented as being less serious than the coal miners' dispute, with considerable amusement aroused by some of the more novel alternative fuel sources, not the least being a battery-powered car with recharging from a windmill on the roof!
.Alas, there is nothing lighthearted or obvious about one of the effects on air safety which arise from the fuel crisis, although so far only on flights out of certain United States airports. While the passenger may travel in blissful ignorance, a fundamental and deadly serious question of safety could arise out of what might normally be only a minor accident.
It is easy to over-simplify many questions relating to air safety, but on certain occasions those who should know better use complexity as a refuge.
In technical terms, airlines operating out of the United States have found themselves frequently unable to obtain their usual jet fuel, known as JP1, and instead have been forced to use another fuel known as JP4. More correctly, the respective titles of these two fuels are Jet A and Jet B, since the latter is JP1 minus a number of additives thought desirable for military aircraft. In practical terms, Jet A, or JP1, is safe, while Jet B is dangerous and its use has been discouraged over the years by the authorities, although only Australia; with one of the best air safety records, has actually banned it.
Lord Brabazon, one of this country's most notable aviation pioneers and at one time chairman of the Air Registration Board, the predecessor of today's Civil Aviation Authority, believed in calling a spade a spade.
He described JP1 as paraffin (normally it is called kerosene) and JP4 as petrol. On one occasion, he poured out a puddle of JP1, stood in the middle of it and dropped a lighted match, which promptly fizzled out. He then challenged those who described the two fuels as being equally safe to repeat the performance while standing in a puddle of JP4, but there were no volunteers!
Yet, the Civil Aviation Authority today has been going to great lengths to minimise the difference between the two fuels, at least as far as the public and the media have been concerned. At some risk of contradicting it self, it has also quietly reminded the airlines that they should not refuel an aircraft with JP4 while the passengers are still on board.
Just what is the difference? The most dramatic must be a difference in flashpoint of around 60 degrees centigrade, with JP4 in its civil form being able to ignite at" as low a temperature as 20 degrees below freezing, while JP1 remains safe at 40 degrees above centigrade. There is more: JP4 will explode, but JP1 will only do so if it is vapourised, which it does not do easily and in fact usually only does in the engines, with pilots trained to cope with engine disintegration anyway, since a number of causes could be behind this.
Accidents happen, but the point is to be able to cope with them and minimise their effect. If an aircraft has JP1 in its tanks and the undercarriage collapses on landing, it would be bad luck indeed to lose any of those on board. Contrast this with JP4, which would leave the possibility of escape to luck. A Boeing 707 struck by lightning in the United States during 1963 exploded, but would not have done so had JP1 been the fuel carried. A year later, another 707 hit a construction vehicle at Rome airport, with the loss of fifty people, again with JP4 as the fuel. The rate at which a JP1 fire spreads can be measured in inches per second, while a JP4 fire spreads at a rate of yards per second. If nothing else, this must raise one very important question: does the ninety seconds emergency evacuation time allowed by the British Civil Aviation Authority and the United States National Transportation Safety Board take into account the use of JP1 or 3P4 fuel? To allow for the fact that one side of the aircraft may be on fire and the flight deck crew incapacitated, the British regulations treat the evacuation situation as darkly as possible by stipulating that ninety seconds is the time allowed using only one side of the aircraft for escape, and with the help of the cabin crew only — anything else is a bonus towards even faster evacuation. At the rate of spread of a JP4 fire, the whole area around an aircraft would be on fire before the evacuation could really get under way.
Only operations in extreme cold can justify the use of JP4 in a jet aircraft, since it then possesses certain qualities which make it a more practical fuel. It is also suitable for piston engined aircraft because JP1 cannot deliver enough power for this type of engine.
To date, the Civil Aviation Authority, which replaced the old Air Registration Board and Air Transport Licensing Board, has done much for British civil aviation, but there can be no doubt that the minimising of the risks of JP4 is a retrograde step. If Lord Boyd-Car penter, the CAA's chairman, has any doubts, let him contemplate repeating Lord Brabazon's experiment, and then attempting the same with JP4, or "petrol"!
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