Date: 201508
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Aircraft: Gulfstream V / G500 / G550
Operator: Fractional
Mission: Passenger
Flight phase: Parked
Aircraft component: Interior Door
Component problem: Malfunctioning
Reporter organization: Fractional
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Workload; Troubleshooting; Confusion; Communication Breakdown; Distraction
Second reporter function: Pilot Not Flying; First Officer
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Pre-flight
Result: General None Reported / Taken
Contributing factors: Aircraft; Chart Or Publication; Procedure; Manuals; Company Policy
Primary problem: Chart Or Publication

Narrative: The First Officer (FO) and I went out to the aircraft to do preflight inspections and prep as we were assigned tentative duty. Upon arriving at the aircraft; I began to review the aircraft logbook while the FO was in the cockpit looking things over. I noticed the Main Entry Door Acoustic Curtain/Door System had been written up (MEL 52-6-0) as 'will not move out of lock/secured position; locking pin does not move when handle is turned'. I began to inform the FO verbally. We both began to look at the door and discuss how the door being locked in the open position might be a safety issue as access to (3) CB door panels that included the LEFT ELECTRONIC EQUIPMENT RACK (LEER); the power distribution box; and other important relays were blocked by the door in its current position. I then called the Chief Pilot to inform him of our concerns with the Acoustic Door being secured in the fully open position. I informed him that we were uncomfortable as it blocked access to important CBs; which prevented us from complying with the SOPs including the preflight safety checklist. The Chief Pilot listened to my concerns; and advised me that the MEL program was approved by the FAA and that the aircraft was airworthy.The CBs inside these panels include/affect many important systems; relays; and contactors. Access to these (3) CB panels is necessary for both on the ground (pre-flight SOPs) and during flight (as referenced in both normal and emergency checklists in the QRH). While the aircraft may be legal to fly; I feel the inability to check/confirm/access the (LEER) CBs prevents us from being able to fully comply with our SOPs as we are unable to confirm that all CBs are in (per our preflight safety checklist). Finally; should an issue arise (involving an affected system) while in flight; this blocked access would prevent us from effectively running associated checklists as required by our aircraft QRH. I believe this MEL (52-6-0) needs to be reviewed more in-depth. I do not feel that it fully addresses the safety concerns and issues created with the Acoustic door blocking access to such important CB's located within the (3) access panels.This event did not disrupt a live trip; as we were only tentatively backing up other flights in the area and did not fly. I believe this MEL (52-6-0) needs to be reviewed more in-depth. I do not feel that it fully addresses the safety concerns and issues created with the Acoustic door blocking access to such important CB's located within the (3) access panels.


Second narrative: In the QRH; the warning messages; caution messages; and advisory messages sections addresses resolving issues and problems on the ground and in flight with the circuit breakers behind the panels mentioned that is being block by the Acoustic Door.The FOM; QRH; SOPs and check list cannot be complied with because of MEL 52-6-0 and therefore presents a safety of flight concern and as a result this aircraft should not be flown until the Acoustic Door problem is resolve.


Synopsis: A G550 MEL 52-6-0 permitted dispatch with the Main Entry Door Acoustic Curtain/Door System immoveable in the lock/secured position preventing access to LEFT ELECTRONIC EQUIPMENT RACK and POWER DISTRIBUTION BOX circuit breaker panels. The flight crew questioned the aircraft's airworthiness because the QRH requires access to that area for certain abnormal procedures.