An Inspector reports on events that contributed to his not verifying whether the #1 and #2 main tires that were replaced; had their retaining nut spacer re-installed; during his RII inspection of the wheel nut torques and safety bolt installations. All four main tires on the Gulfstream G-200 were later found without their wheel spacers installed.

Narrative

Gulfstream G-200 in for #1 and #2 main tire change due to wear limits. These tire/wheel assemblies were removed; new assemblies installed and axle nut installed; torqued and safetied with screws through nut into axle (done in reverse order of disassembly). I verified (asked the mechanics what torque they need) was told the pre-torque valve; and final torque valve and watched; as nuts were torqued and safetied. Done for double buy back inspection. This is where the spacer was left out. Between the wheel and axle nut. Did not notice this because both wheel/tire assemblies were missing a spacer and the nut torqued down properly. There was no play side to side of wheels and safety screws aligned with holes in axle. It was not noticed until May 2009 at another maintenance base when the #3 and #4 main wheel and tire assemblies were changed that the spacers were missing. Then the #1 and #2 wheels were verified to be missing the spacers. This leads back to January 2009. This aircraft was at another maintenance base where all four wheels were replaced. This is where the spacers were originally left off. As a mechanic; I feel we were set up for failure by the previous vendor. Then the mechanics who replaced #1; 2 MLG wheels only used the manual for torque valves. Third; as Inspector I should have caught the missing spacers. Ways that I should have noticed was by verifying maintenance manual was out and in use. Reading over procedure myself and checking illustrated parts catalog (IPC) for parts breakdown. Not relying on other mechanics to have read procedure. After talking with other mechanics familiar with the G-200 this problem of the spacer missing between the axle nut and wheel assembly is very common. Maybe the manufacturer should look at ways to modify this so it does not happen again.