Ram Air Turbine (RAT) deployment actuator Service Bulletin (SB)

Effectivity Global Express, Global 5000 and Global 6000 aircraft

ATA 24-23

On Feb. 22, 2019, Bombardier issued Service Bulletin (SB) – Special check/modification - Emergency AC-Power supply – replacement of the Ram Air Turbine (RAT) deployment actuator part no. BZ02001-01 (Lucas Part Number (P/N)), GL456-1301-1 (Bombardier P/N). The SB provides instructions to inspect and return the Ram Air Turbine (RAT) deployment actuators P/N: 762830 (Collins P/N) equipped with the affected piston rod to the supplier for a modification. The intent of this Forum article is to remind operators to schedule the replacement of the affected RAT deployment actuator within 36 months of the SB release to get the deployment actuator at no cost as well as highlight that there are AD’s issued mandating the incorporation of these SBs.

Bombardier equivalent SBs:

• 700-24-090 – Global Express XRS

• 700-1A11-24-029 – Global 5000

• 700-24-5015 – Global 5000 Vision

• 700-24-6015 – Global 6000

Airworthiness Directive (AD):

• TC AD CF-2019-38

• EASA: AD CF-2019-38

• FAA AD 2020-12-14

The SBs introduce actuator part number 762830A, which has an improved anti-fretting manufacturing process. The new part design integrates a non-metallic sleeve assembled into the bore of the gland housing instead of a coating process to prevent galling.

The investigation was initiated after a field event where the actuator piston rod and gland bonded together (galling) which resulted in the RAT failing to fully deploy. The affected actuator was built prior to serial number 0275 and was equipped with piston rod P/N: 763795.

The suspected list of actuators (P/N 762830) Serial Number (SN) which require replacement are the following:

Operators affected by the SBs listed above are mandated by the ADs, if not already done, to request the incorporation of this SB at the earliest opportunity.