Gulfstream Summer 2007

• Main Gear Support-Structural Inspection
• GV Elevator Bonding Jumpers

Main Gear Support-Structural Inspection

— Jim Overheul

This inspection is required at different times depending on which Gulfstream model you operate. If you operate a GII, GIIB, or GIII aircraft then the Main Gear Support-Structural Inspection will be required at each gear removal, unless previously accomplished within the last 2000 landings. If you operate a GIV using the Gulfstream MRIP (Manufactures Recommended Inspection Programs), this inspection is required at landing gear overhaul unless accomplished within the last 2000 landings. If you operate a GIV using the MSG-3 (Maintenance Steering Review Board Program) this inspection is not required at this time.

We have complied with several of these inspections on all of the models described in the first paragraph. In all the cases where the forward main landing gear trunion spherical bearing were installed dry we have identified various levels of corrosion in the bearing installation bore. The spherical bearing installations were wet installations occurring at about GIV S/N 1259 and subsequent. All models and serial numbers prior to that were dry installation unless they have been repaired per Gulfstream repair drawings SE25732901 GII, GIII, GIIB/ SE45732901 GIV forward lugs and SE05732901 GII thru GIV aft lugs. We have done several of these forward and aft sponson rib-trunion repairs and on the forward lug it has taken anywhere from 0.005” to 0.030” to clean-up the installation bores.

Since the forward lug has very limited rework limits (0.030” maximum GII, GIII, GIIB, GIV without ASC190 installed and 0.020” maximum GIV with ASC190 installed) we have had a couple of GIV operators (ASC 190 and MSG-3) elect to comply with this inspection prior to the scheduled inspection interval while the main landing gear was removed for repair. Corrosion was identified in these cases and took anywere from 0.005” to 0.015” to clean up the installation bores. Identifying early corrosion in the main landing gear sponson rib forward lugs and making the necessary repairs may save you a sponson rib assembly replacement in the future. To comply with these repairs it takes specialized boring equipment, so make sure your service provider of choice is equipped to meet your maintenance needs.

If you have any questions about this or any Gulfstream issue, please contact me at 269.969.8477.

GV Elevator Bonding Jumpers

— Jim Overheul

While complying with some recent GV Horizontal Stabilizer Trailing Edge (left/ right) Zonal Inspections (CMP’s 551015/551016) it was noted all of the elevator bonding jumpers were broken. Some aircraft had the Fokker style bonding jumpers with part number FON9-1981-4BB6 and others had part number MS25083-4BB6 bonding jumpers installed.

Correct installation is very important to maintain control surface lightning protection bonding and static discharge protection.

1. Orientate terminal-end to achieve maximum bonding jumper life.
2. Avoid sharp bends and loops because of the susceptibility to breakage when subjected to the inductive forces created by lightning current.

The changing of the elevation bonding jumpers is very labor intensive because of the installation design. The elevator ballast weights (inboard and outboard) will have to be repositioned (very difficult with elevators installed) to allow access to the head of the attachment screw of the bonding jumper terminal-end.

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