Installation of repaired windshield and side windows

Effectivity: Challenger 300/350/3500 aircraft 

ATA: 30/56 

By: Yanick Fournier - Technical Services 

This article is to advise that operators may receive “repaired” flight compartment windshields and side windows for Challenger 300/350/3500 aircraft. Following a vendor quality issue, a review of the aircraft safety and engineering documents was conducted. This review resulted in allowing the vendor to cap and stow one sensor during repair, considering that this will have no impact on the operation of the transparencies. 

The transparencies are equipped with three (3) sensors to read the temperature. Only one sensor is required to keep the unit functional. In normal operation, the controller will monitor the sensors, disregard a defective sensor, and continue to operate until all sensors have failed. In some cases, the sensor failure mode can affect this system logic, creating a nuisance HEAT FAIL message. In such cases, the vendor can now disable the defective sensor and return the transparency in service as a “repaired” unit at a discounted price. 

To allow installation of “repaired” transparencies, the AMM task 56-11-01-400-802 windshield installation and task 56-12-01-400-802 side window installation were revised in May 2024.  

The added note in the AMM specifies that a unit with a sensor disabled can be installed if the associated In-Service Mod Sum (ISMS) IS100-30-0002/0003/0004 and 0005 is incorporated. The incorporation of the ISMS ensures that operators have a trace of the modification and to keep the wiring installed as per standard. 

Maintenance personnel should be aware that when a windshield or side window is received with a sensor disabled by the vendor, the part is serviceable and should not be returned. The disabling of the sensor should be noted, by the vendor, in the part documentation (Form 1 / 8130) and the disabled sensor will be physically identified (connecting terminal capped). This information demonstrates that the part is not Dead On Arrival (DOA) and may be installed on the aircraft. 

Bombardier would like to take this opportunity to mention that in case of an intermittent HEAT FAIL message posted on the aircraft, it could be linked to a defective sensor. For these cases, the ISMS IS100-30-0002/0003/0004 and 0005 are available on our portal library. The ISMS instructs on how to bag and stow the wiring of a sensor with this specific failure mode and continue to operate the transparency without any limitations. Advisory Wire AW300-30-0418 can also be consulted for additional information on this issue.