Challenger: Troubleshooting Environmental System Squawks

April 2010

As spring and summer temperatures begin rise, so do the number of environmental system squawks. For all aircraft that have an air cycle machine, the discomfort of passengers and crew become more evident as the airflow and temperature are reduced.

Airflow reduction is simple. Hot air is being diverted to the cooling packs and cooling air requires more energy. As this natural energy drain occurs, leaks, cooling turbine, intercoolers, regulators and air supply sources are now more prone to show their deficiencies if they are not up to specification.

The most efficient way to determine the cause of this squawk is to have your Challenger MRO take measurements of the environmental system. This evaluation will direct an experienced technician to the area of the system most likely to be the cause of cabin discomfort.

Advantages of Environment System Evaluation

1. Economic Savings: Without the system evaluation, determining the cause is somewhat of a guessing game and the cooling turbine is usually the first unit to be changed. Randomly changing out parts and components because the duct work “feels” warm or the air flow from a aft cabin WEMAC “seems” low, is expensive and can result in added expenses due to changing parts and the squawk is still not settled.

Duncan Aviation Recommendation

DO NOT change the cooling turbine unless it is locked up and all other sources have been ruled out. Although a cooling turbine with higher torque than specified is not ideal; this is a very expensive unit and our experience tells us it is typically not the primary problem.

2. Downtime Savings: The environment system evaluation can be performed on-the-road at any location with little interruption to your busy flight schedule. In fact, flying can continue immediately after the evaluation has been performed. The impending results take the guesswork out of the equation and establish a recommended maintenance plan. A complete maintenance plan and a quote for the work are typically received within three days.

Duncan Aviation Recommendation

Take advantage of the next time your Challenger is scheduled-in for necessary inspections. The maintenance for this squawk can be easily performed while the interior is removed for other services.

Have your system tested and fixed before your passengers or crew begin to complain about uncomfortable cabin temperatures.