Date: 201410
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Light: Daylight
Aircraft: PC-12
Operator: Air Carrier
Operating under: Part 135
Mission: Ferry / Re-Positioning
Flight phase: Parked
Aircraft component: Compass (HSI/ETC)
Component problem: Malfunctioning
Reporter organization: Fractional
Reporter function: Captain; Pilot Flying
Human factors: Communication Breakdown; Confusion; Situational Awareness
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Maintenance
Detector: Person Flight Crew
When detected: Taxi
Result: Aircraft Aircraft Damaged; General Maintenance Action; General Flight Cancelled / Delayed
Contributing factors: Procedure; Incorrect / Not Installed / Unavailable Part; Human Factors; Equipment / Tooling
Primary problem: Human Factors

Narrative: We airlined to ZZZ to pick up a Pilatus PC-12 aircraft after a scheduled maintenance inspection by XXX Aircraft Maintenance at ZZZ. We received a trip sheet to reposition from ZZZ to ZZZ1; so we went from airline terminal to XXX Aircraft Maintenance. The First Officer (F/O) went out to preflight and I asked to speak to someone from maintenance familiar with the work done on our airplane.  Maintenance Supervisor X reviewed the paperwork for the inspections performed. As a result; I told my F/O the nature of the maintenance performed and asked him to be very thorough in the preflight while I was planning the flight and checking weather.  F/O called me and said an access panel was open on the right front lower side. He sent me a photo which I sent to our Air Carrier Maintenance Control. I found XXX Aircraft Maintenance Supervisor X and asked him to inspect inside the access panel to make sure there was nothing left inside and to install the panel. XXX Maintenance accomplished that. This took some time and delayed our departure.  Early evening; Operations Control called me and I gave the Customer Service Representative (CSR) outbound times to ZZZ1. We started the aircraft and during post start instrument checks; I noted that my EHSI and RMI showed a heading of approx 085 and the right side EHSI showed approx 175 degrees which matched the mag compass and the acft orientation on the ramp. We had a HDG flag on pilot and CP EHSI. We tried all the normal procedures to correct the problem. All CB's were in. Each time; when selecting the slave position after setting the card manually; the card would abruptly rotate back to a heading of 085. I called maintenance control and they got avionics on the phone with me. We went through a number of steps to try and correct the problem but the results were the same. I taxied approx 100 feet forward on the ramp to eliminate the possibility of metal under the ramp causing the problem. Still had same results. Acft was approx 500 feet from nearest hangar on a concrete ramp. I shut down the acft and talked to Maintenance Control and Flight Operations. Maintenance Control said we could MEL defer the EHIS/AHRS problem and I reminded Maintenance Controller X that we have a Company Safety bulletin that precludes operating in IFR or night with a single AHRS. I recommended to Controller X that we get the problem fixed right there at XXX Aircraft Maintenance before flying away anywhere; even under day VFR. My reasoning was that I suspected XXX Maintenance had caused the problem and would know where to look for the problem since they were the ones who had just completed the maintenance.  Maintenance Control arranged for XXX Maintenance to come out to the plane and see if they could find the cause. Maintenance Supervisor X I had spoken with prior; came out and removed the flux valve access cover under the Left-Hand (LH) wing and found a flashlight laying inside. After removing the flashlight and reinstalling the panel; I asked for a Ground Power Unit (GPU) and we powered up the acft and avionics with GPU power and the EHSI/AHRS worked normally and we had no Flags.If we had deferred the AHRS problem using the MEL and then continued to fly; the large piece of FOD in the left wing could have caused a catastrophic flight control malfunction. Maybe the risk of this is very low; but the possibility cannot be ruled out. Positive tool control is a safety measure that has long been required in the U.S. military and I suspect many airline operations. I do not know if this is a part of the safety system at XXX Aircraft Maintenance or at our company. But; a properly implemented tool control process could have eliminated this from happening. The mechanic would have known his flashlight was missing before completing all paperwork; signoffs; and releasing the acft for flight. I suspect time or cost pressures may have been a factor in XXX Aircraft Maintenance rushing the inspections and failing to detect the uninstalled access panel. It is also possible that the intensity of our company operations may have caused our company to place a tight deadline on XXX Maintenance to get this airplane back into service.After I identified this problem to Operations Control; the primary consideration seemed to be to get the plane back into operation for the following morning mission; rather than getting the AHRS/EHSI problem investigated and corrected before leaving the maintenance facility at ZZZ. I think this can be a wakeup call for managers in Operations to pause and consider safety implications and place primary focus on safety over and above the operational schedule. There are other options such as chartering acft to complete the schedule rather than taking an unnecessary risk.




Synopsis: Captain describes his efforts to have his company Maintenance Control direct a Contract Maintenance provider to troubleshoot the cause of his left EHSI and RMI showing a heading of 085 compared to the right EHSI of 175 degrees that matched the Magnetic compass and aircraft orientation. Maintenance flashlight found in the left wing Flux Valve access area of the Pilatus PC-12 aircraft. Issue of Tool Control also raised.