Gulfstream V / G500 / G550
Maintenance Powerplant; Maintenance Airframe; Maintenance Inspection Authority
Maintenance Avionics 22; Maintenance Inspector 10; Maintenance Lead Technician 6; Maintenance Technician 22
Communication Breakdown; Confusion
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Maintenance
General Maintenance Action
Procedure; Logbook Entry; Aircraft
On DATE; Company Maintenance Technicians had replaced the existing OEM Taxi Light Installation with Whelen Aerospace Technologies Boom Beam Taxi light System IAW STC# ST02893AT on G-550 X. I was intermittently involved in the installation and had inspected the completed installation by request of the installing technician. I was notified on DATE1 of the intent to fly the aircraft in the evening so the pilots could observe the performance of the new lights. On the day of the flight I had been working on other projects and was preparing to depart for the day when the pilots arrived and asked if we had completed our maintenance pre-flight inspection. I discovered that the preflight had not been completed and proceeded to perform the preflight with the installing technician. Part of our preflight includes a review of the maintenance records and after reviewing the documents in Gulfstream's Computerized Maintenance Program (CMP) determined that there were no outstanding maintenance items. I asked the installing technician if the 337 had been completed and he responded with 'It's on Mechanic's (the Certifying IA) Desk' which I assumed to mean that it was complete.I signed the maintenance release and preflight form and departed for the day. The aircraft flew under part 91 rules that evening without incident.On DATE2 I spoke with Mechanic and discovered that although he had completed the inspection and all other associated paperwork before the flight; he had not signed the IA block of the 337 until the evening of the DATE3.Overall there were no unsafe conditions; only an oversight in paperwork. Upon discovery of the documentation error I self reported to my Supervisor and filed this report. An internal investigation has been initiated by my supervisor.
Technician reported an aircraft operation in Part 91 flight without all documents signed and the log book update correctly.