Men Who Killed Qantas - Matthew Benns [53]
Problems arise when there is any kind of oil leak in the front of the engine. A worn seal and a small leak are enough. Mobil Jet Oil 2 is harmless enough in a can, but superheat it in a jet engine and it breaks down into a deadly cocktail of airborne carcinogens and organophosphates, including the particularly nasty tricresyl phosphate, or TCP, which attack the nervous system and can cause long- and short-term brain damage, and motor neurone disorders such as Parkinson’s disease. When cooled and pumped into the cockpit and cabin of a modern jetliner, this chemically laced air smells oddly like blue cheese or vomit.
Airlines have long disputed these claims, which are now being independently researched at the University of Washington. The Civil Aviation Authority in Australia has also set up an independent panel of experts to determine the extent of the problem and to decide if further investigation is necessary.
On a new plane toxic air is not usually a problem because there is little wear and tear and consequently few leaks. In fact, the new Boeing 787 Dreamliner does not use ‘bleed’ air, cabin air bled directly from the engines, at all and so it will never pump toxic air into the cabin. But if you have an aircraft operator with an existing and ageing fleet, who is on a cost-cutting drive and may not be doing the maintenance quite as quickly as desired, an oil leak can be pumping chemically laced fumes into a cabin for days, weeks or even months.
The Qantas Boeing 747 that operated as QF26 out of Los Angeles has the registration number VH-EBW and a shocking maintenance record. The problem on VH-EBW was an oil leak in the auxiliary power unit (APU), a tiny jet engine in the tail of the plane that provides power to the electrics and air conditioning while the plane is stationary and waiting for the engines to be started for take-off. ‘These units are not really important and are usually just run into the ground,’ said a Qantas technician who did not want to be named. ‘When the oil leaks it flows to the air conditioning unit in the middle of the plane and settles on the water separator. The air conditioning unit separates the water from the air that is pumped into the cabin. The separation process dislodges the oil, which is then turned to gas by the superheated air that comes in from the engine. That gas is then pumped into the cabin with the cooled air.’1 The APU is turned off before the plane takes off so the smell in the cabin only lasts as long as it takes to burn off the leakage from that sector.
Qantas keeps thorough logs on all its planes. The technical defect log for VH-EBW shows the APU needed to have a quart of oil added on 11 October 2006, nine months before the flight engineer was overcome on the flight from Los Angeles to New Zealand. Another quart was added a week later on 18 October 2006. On 15 November it needed 1.5 quarts of oil. Then the fault light started flashing – and kept flashing. On 19 January the APU was topped up with 1.5 quarts of Mobil Jet Oil 2, two quarts on the 24th and 1.5 litres on the 31st. Month by month the engineers kept topping up the oil. Where was it going? They checked for external leaks and replaced the oil tank cap but still the oil level kept dropping. More oil was poured, quarts and quarts of it. The APU oil tank only held four quarts of oil. In April 2007 it burned through almost two full tanks of oil. In July it went through two more tanks.
Four days before the Los Angeles toxic fumes incident, the log showed that an inspection of the APU found the cooling air manifold and APU firewall were wet with oil. The air cooling fan seal was replaced and the tired old APU pushed back into service. On 10 August, less than two weeks after