Honeywell has released SB (Service Bulletin) AS 907-76-9021 Rev 0 dated May 13, 2016, regarding the possibility of water entering the ECUs (Electronic Control Unit) after the aircraft is parked in the rain for an extended length of time. This may lead to unscheduled maintenance and expense, aircraft dispatch delays, Loss of Thrust Control (LOTC) events and the possibility for inflight shut downs.
This SB is relevant to the following aircraft:
- Bombardier Challenger 300 (HTF 7000)
- Bombardier Challenger 350 (HTF 7350)
- Gulfstream G280 (HTF 7250)
- Embraer Legacy 450 (HTF 7500)
- Embraer Legacy 500 (HTF 7500)
Honeywell has categorized this as a CAT 1 SAFETY SB meaning it may require urgent action and may be associated with an FAA AD (Airworthiness Directive). With that being said, this SB, under the Compliance Section E, has recommended compliance be within 400 engine operating hours or 18 months from the date the SB was issued.
The compliance is to access the ECUs and apply sealant to specifically identified areas on the ECUs. The job is estimated at 5.5 hours per side.