Duncan Aviation logo

Gulfstream: G-IV Vertical Stabilizer Drag Angle Fasteners

September 2014

During several recent Gulfstream IV inspections, Duncan Aviation technicians have discovered mechanical fasteners installed in the fuselage drag angles at the base of vertical stabilizer in place of the production installed solid rivets.

The Gulfstream IV Structural Repair Manual is very specific on Rivet Substitution i.e.: It is not permissible to substitute a mechanical fastener in place of a solid fastener.

There have been many revision changes to the Gulfstream IV Maintenance Manual procedure Vertical Stabilizer – Removal/ Installation. Because of this, it is possible if this procedure was the only one referenced during the Vertical Stabilizer removal and installation, then the wrong fasteners may be installed.

There are several documents that may have to be referenced to assure correct fastener installation, such as: 1159CS20153/ 1159CS20154, ASC230, etc.

A Publication Change Request has been requested through the Gulfstream Service Engineering Group for the above noted condition.

Also noteworthy is that Gulfstream IV ASC number 488 (FS 793 Bulkhead Cap Angle-Replacement) references the Gulfstream AMM, Chapter 55, Vertical Stabilizer-Removal/ Installation procedure only.

As of this article, Revision 65 (Dated May 29/14) of the Gulfstream IV Maintenance Manual added a General section that states:

This procedure uses permanent fasteners, therefore is not a typical removal / installation procedure. This procedure provides general guidelines and steps. Engineering documentation for the specific installation will have to be utilized in order to properly accomplish the procedure. Contact Gulfstream Customer Support for further instructions.

Although this article only references the Gulfstream G-IV model, it may be applied to similar models/ variants.