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Concern is growing about the number of pilots and crew being overcome by toxic fumes on airlines worldwide, with fears that hundreds of thousands of passengers might also be affected.
In the latest incident, a Qantas flight engineer was off work for a week after inhaling noxious fumes on the flight deck of a Boeing 747 travelling from Los Angeles to Auckland. Meanwhile, in Britain - where the Department of Transport is to begin a rigorous monitoring programme - crew of one of its biggest budget airlines are refusing to fly part of its short-hop fleet, saying they are too scared to after 10 leaks in the past 15 months.
The Australian and International Pilots Association has put the hard word on that country's leaders. On Friday it issued a challenge to the major political parties, calling for a full investigation into cabin contamination, which it likened to a "toxic time bomb".
Australian Federation of Pilots spokesman Lawrie Cox told the Herald on Sunday the problem stemmed from a design feature in jet aircraft, whereby warm air is bled off the engines and pumped into the cabin. While all pressurised aircraft had an air filter, seals could fail, sending chemical-laced air into the cabin.
Despite the alarming research - another British study last year suggested that almost 200,000 passengers in the UK might be breathing in toxic fumes during flights every year - Cox said manufacturers and airlines, including those in New Zealand, had continued to ignore it.
"We know long-term exposure to misting or burned fuel can cause major health problems, and there's been reports ranging from minor irritation through to incapacitation... They have tried to keep it quiet for years. We have asked for full scientific testing and that has been blocked on each occasion. If we get a major incident where the two pilots are affected it would be a disaster."
The New Zealand Civil Aviation Authority said it was aware of the overseas reports.
However spokesman Bill Sommer said because the Qantas plane in the most recent incident was operating on a certificate issued in Australia, the incident would not be reported to authorities here but would be investigated by the airline and Australian Transport Safety Bureau.
Aircraft flown here underwent a rigorous certification process and were fitted with air filters. The country that issued the certificate remained responsible for the continuing airworthiness of a particular aircraft.
However, Cox said, that did not mean New Zealand passengers and crew were not being exposed to toxic fumes at times.
There was strong evidence - also mentioned in a report entitled Air Safety and Cabin Air Quality in the BAe 146 Aircraft to the Australian Senate - that pilots and crew did not report incidents, either because of employment concerns or lack of knowledge, he said.
Chris Winder, a toxicologist who gave evidence to the Senate BAe 146 inquiry, noted that the toxicity of jet engine oil - Mobil Jet Oil II - had been significantly understated by the manufacturers.
The component of most concern was tricresyl phosphate (TCP) which, when heated to high temperatures, emitted toxic phosphorous oxides.
"One issue of particular concern is development of aerotoxic syndrome in pilots and flight attendants. This is a specific long-term occupational health condition, associated with exposure at altitude to contaminants from engine or other aircraft fluids," Winder has been reported as saying.
However, Air New Zealand's chief medical officer, Dr David Powell, argued the contamination related only to the BAe 146, which the company did not use.
To his knowledge, there had been no instances of flight crew complaining about fumes, or of crew being off sick with poisoning symptoms.
Air New Zealand passenger aircraft used Mobil Jet Oil II, Dr Powell said.
Fright flights
December 2000
Australian Senate inquiry finds exposure to fumes from lubricant oils causes health problems, such as headaches, vomiting, breathing difficulties and partial paralysis for pilots, flight attendants and passengers.
January 2001
26 Alaskan flight attendants win a $725,000 out-of-court settlement from Alaska Airlines after claims of central nervous system damage by exposure to toxic leaks that fouled DC-9 and MD-80 cabins.
November 2002
Two Australian pilots on a flight affected by fumes.
2007
Despite improvements in jet oil formulations and modifications to aircraft, problems continue.
Where do the fumes come from?
Because of the thinness of the air at altitude, aeroplanes need a constant supply of compressed air for the cabin. The engines also need it for combustion and, because this is a convenient source for the cabin air, some of it is bled directly from the engines and piped via the air conditioning into the cabins.
