AD 2007-12-25

You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

Within 20 flight hours after the effective date of this AD: Revise the Normal Procedures section of the AFMs to include the information in the applicable AFM supplement identified in Table 2 of this AD. This may be done by inserting a copy of the supplement into the AFM.

Note 1: For airplanes that are operated under and in accordance with the Joint Aviation Authority (JAA)/European Aviation Safety Agency (EASA) regulations, supervision, and oversight: EASA has advised us that revising the Normal Procedures section of the AFMs to include the information in the JAA Gulfstream AFM revisions specified in Table 3 of this AD, as applicable, is acceptable for compliance with the requirements of paragraph (f) of this AD.

(g) Before further flight following accomplishment of the AFM revision required by paragraph (f) of this AD: Perform a functional check of the forward water system water drain/supply valves and do applicable corrective actions, in accordance with the applicable AFM supplement identified in Table 2 of this AD. Do the functional check at the times specified in paragraphs (g)(1) and (g)(2) of this AD. Either the cockpit flightcrew or certificated maintenance personnel may perform these functional checks. If the water system has been deactivated as part of the corrective actions, the functional checks need not be performed again until the water system is reactivated. Doing the optional terminating action specified by paragraph (g) of this AD ends the requirement for the repetitive functional checks.

(1) Before the first flight of the day.

(2) Before further flight when the airplane is exposed to freezing conditions on the ground after the airplane has been powered down.

Doing the actions described in paragraphs (h)(1) and (h)(2), as applicable, of this AD terminates the functional checks required by paragraph (g) of this AD. After the actions specified in paragraphs (h)(1) and (h)(2), as applicable, of this AD have been done, the applicable AFM supplement specified in paragraph (f) of this AD may be removed from the AFM.

(1) Inspect to determine the part numbers of the forward water drain/supply valves, in accordance with Part II of the Accomplishment Instructions of the applicable alert customer bulletin identified in Table 1 of this AD. A review of airplane maintenance records is acceptable in lieu of this inspection if the part numbers of the drain/supply valves can be conclusively determined from that review.

(2) Replace any water supply valve having part number (P/N) 4E4151-1 with a new, improved water supply valve having P/N 4E4491-1, and any water drain valve having P/N 4E4151-3 with a new, improved water drain valve having P/N 4E4493-1; in accordance with Part III of the Accomplishment Instructions of the applicable alert customer bulletin identified in Table 1 of this AD. If the P/N of any water drain/supply valve is missing or cannot be determined, replace the water drain/supply valve with a new, improved water drain/supply valve, as applicable.

Note 2: Help is available from Gulfstream for determining a missing or otherwise indeterminate part number of any water drain/supply valve.

(i) As of the effective date of this AD, no person may install a water supply valve having P/N 4E4151-1, or a water drain valve having P/N 4E4151-3, on any airplane.

Although the alert customer bulletins referred to in this AD specify to submit certain information to the manufacturer, this AD does not include that requirement.