Date: 201808
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Aircraft: Gulfstream IV / G350 / G450
Operator: Air Taxi
Operating under: Part 135
Flight plan: IFR
Mission: Passenger
Flight phase: Landing
Airspace: Class C ZZZ
ATC / advisory: Tower ZZZ
Aircraft component: Main Gear Tire
Component problem: Malfunctioning
Reporter organization: Air Taxi
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Human factors: Situational Awareness
Second reporter function: Pilot Not Flying; First Officer
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Diverted; Flight Crew Landed in Emergency Condition
Contributing factors: Aircraft; Procedure
Primary problem: Aircraft

Narrative: I departed ZZZ airport. After departure we received a CASS indicating a service door was open. It only says 'service door' and not which service door. My worry was that it was a door that could rip off and go into the engine; such as; the O2 or fuel door. We were a few thousand pounds overweight and Gulfstream requires a g-meter inspection after landing over weight. I felt I could touch the aircraft down very smoothly and use thrust reversers to slow to 60 KTS before applying light brakes. I decided a return to the airport for an overweight landing was the best solution; since I was worried about a door ripping off and going into the engine. We preceded back to the airport and landed. The landing was extremely smooth and brakes weren't applied until 60 KTS. The brake temperatures appeared normal for any landing. We taxied to Atlantic to check the service doors. All the service doors were verified shut; so we opened each one and closed it and the service door light extinguished. We determined that the door must not have had proper contact with the micro switch; but now we felt it was resolved so we didn't call maintenance. Since everything appeared fine and the touchdown was smooth; we decided to depart again after checking the brake temperatures. Maintenance was never called to check the g-meter. I have a long history of being safe and doing everything by the book. However; I made a severe lapse in judgment; and I put passenger convenience before safety. At no time did I feel I was being unsafe in the moment; but in hindsight; aircraft limitations are designed for safety. Looking back on it I should have respected the aircraft limitations; and I shouldn't have thought that I know better than the aircraft limitations. We also should have had maintenance check the service door light prior to departing. The G4 is an older aircraft and occasionally we'll get a false indication of that the service doors are open due to vibration or poor contact on the micro switch. It's common practice to verify that the doors are closed and pilots often continue without contacting maintenance; but I shouldn't have gone without having maintenance check it out. The service door light never came back on after this; but that doesn't make it right not to contact maintenance. When we departed again we blew a main tire just prior to VR. I'm not sure what caused the tire to blow; because we landed softly and monitored brake temps prior to departing; however; if I followed all the aircraft limitations and/or had maintenance inspect the g-meter; then I wouldn't have anything to worry about. I learned a great deal from this experience. The biggest thing I learned was to follow all limitations; regulations; and procedures. In the Part 135 world; we are often pushed to just get the job done and this is a concern. I'm a guy that prides myself on always following the regulations; aircraft limitations; and safety is my number 1 priority; however; I let the pressure to get it done get to me this day; and I'm not happy with the decisions that I made. I made decisions that I typically never would make and never imagined that I would make. Never again will I let the pressure to get the job done cloud my judgment but never again.


Second narrative: [Report narrative contained no additional information.]


Synopsis: Gulfstream flight crew reported that two main landing gear tires failed on rotation.