Gulfstream Summer 2004

• Why Wait?
• Flap Follow-up and Warning Switch Assembly
• Thrust Reverser Overhaul / On Condition Inspection

Why Wait?

— Ron Hall

The Eurocontrol “Elementary Surveillance” mandate (Flight ID) is scheduled for March 31, 2005, for all IFR and VFR flights within European Civil Aviation Conference (ECAC) countries. If your Gulfstream is not equipped for this mandate, now is the time to take action. The current turntime for Flight ID equipment is seven to ten days with advance scheduling. Turntime in the fourth quarter could reach two weeks. Call our Gulfstream avionics expert, Dennis DeCook, to learn more about this or any of the upcoming mandates to be certain you are legal to roam the entire planet.

Dennis can be reached by calling 800.525.2376.

Flap Follow-up and Warning Switch Assembly

— Jim Overheul

Several recent inspections and troubleshooting scenarios have led us to the flap follow-up and warning switch assemblies.

During inspections, we have found several aircraft that required replacement or repair of the wiring from the flap follow-up and warning switch. The damage was due to the Skydrol attacking the insulation of the wire which exposed the conductor of the wire. In all cases the flap follow-up and warning switch wiring pigtail had no specification markings on them.When the wire was exposed to Skydrol for less than 24 hours, the insulation became twice its size and very soft. There is also a vinyl cover on the pigtails that are affected by Skydrol. This seems to only affect the flap follow-up and warning switch assemblies with the solid color (off-white) wire pigtails on GIIs and GIIIs. It does not seem to affect the newer flap follow-up and warning assemblies with multi-color and color stripe identification wire pigtails on the GIVs. Routine inspections, proper routing, and protection during maintenance, along with expedited repairs of hydraulic leaks in this area all play a major roll in deterring damage to wiring.

During troubleshooting, several intermittent faults have been traced back to the flap followup and warning switch assembly. In all cases the lower switches in the assembly were corroded due to water intrusion. Since all the flap limit switches are located on the bottom of the assembly, the corrosion affected the position operation switches (S1 through S6) before the flap sub system switches (S7 to S12). In one case, water was still present inside the assembly at time of cover separation. This is one of those items that is not called out to inspect but it doesn’t take long to remove the cover and inspect the switches and the o-ring integrity of the assembly. This issue is another reason not to pressure wash your gear or gear wells. For more information, contact Jim Overheul at 800.525.2376 or Doug Donahue at 269.968.8905.

Thrust Reverser Overhaul / On Condition Inspection

— Jim Overheul

Gulfstream GII, GIIB (ASC 175 compliant), and GIII operators should be aware that the 4000 landing Thrust Reverser overhaul interval could be extended to 5000 landing overhaul. Installation of ASC 344 or 344A and ASC 384 before 4000 landings in the GII/IIB are needed to meet the criteria for this extension. For GIII models, installation of ASC 119 or 119A and ASC 171 before 4000 landings are needed.

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