2.10 During the inquiry the number of BAe 146 aircraft operating in Australia changed. On each occasion that Ansett, Qantas or National Jet Systems appeared at public hearings the Committee was brought up to date with the current number of BAe 146s then being operated in Australia.11
2.11 The BAe 146 is configured in Australia to carry about 70 passengers with a normal air crew of five; two pilots and three flight attendants.
2.12 In November 1999 Ansett Australia told the Committee that of its 900 pilots, 165 were regularly flying BAe 146 aircraft.12
Source of air in the BAe 146 cabin
2.13 The Committee was given a detailed account by AFAP of the air source and circulation system employed on jet passenger aircraft. A concise description is as follows:
The engine comprises a fan module, a high-pressure compressor, a combustion chamber and a turbine section. High pressure compressed bleed air is ducted from the rear of the final stage of the high pressure compressor, and is used to pressurise the cabin and to provide aircraft air conditioning (heating) and engine pneumatics. Thus the engine air is used to provide in flight air, pressurisation and air driven systems.13
2.14 The Committee was also provided with a detailed description of how the system used to bring air into the BAe 146 from the engines operated:
The bleed air is air that has been passed from the engine air intake through the engine compressor and then bypasses the engine combustion chamber as it is bled off through the engine pylons. It is then diverted to various systems as well as ducted downstream through the environmental control system to the cabin and flight deck.
As the air is ducted to the rear of the aircraft, it enters 2 air conditioning packs. The air conditioning packs are fed independently from the left or right engines and do not interconnect. One air conditioning pack can supply cabin air and pressurisation requirements for the whole aircraft. One engine per side can feed its related air conditioning pack.
The engines on the left wing (engines 1 & 2) service air con pack 1, which provides air to the flight deck and passenger cabin. Engines 3 & 4 on the right wing supply pack 2, which supplies air to the cabin.
11  For example see Ansett Australia, Evidence, 1 May 2000, p 242 
12  Ansett Australia, Evidence, 2 November 1999, p 61 
13  Submission 14A, AFAP, p 2 

The Auxiliary Power unit (APU) in the BAe 146 is either an Allied Signal Garrett or Sundstrand unit. The APU is a small turbine engine that supplies air and/or electrical power when the aircraft is on the ground and for certain periods of flight, such as take off or landing, when air cannot be spared from the main aircraft engines. 14
2.15 The BAe 146 is designed to operate with the air conditioning system re-circulating a proportion of cabin air. It is generally considered that re-circulated air improves humidity levels in the aircraft cabin and cockpit and is a feature designed to reduce symptoms of watering eyes as well as nasal and throat dryness caused by dry air.15
　
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