B737 flight crew reported multiple MELs on the aircraft required a complicated and unusual engine start sequence involving maintenance assistance. Flight crew recommended to oncoming crew that they refuse the aircraft.
Synopsis
B737 flight crew reported multiple MELs on the aircraft required a complicated and unusual engine start sequence involving maintenance assistance. Flight crew recommended to oncoming crew that they refuse the aircraft.
Narrative
The previous crew refused the airplane. That should have been the first warning. The airplane had 2 maintenance discrepancies: number 2 engine starter needed manual operation and the APU could only be used for electrical. This is why the previous crew refused the airplane; because they were supposed to go to ZZZ1 and that location only had Contract Maintenance which would most likely not do the manual start valve operation. As I found out; there was more complexity to this problem than that. What we needed to do was an air start on the number 1 engine followed by a cross bleed start on number 2 engine using manual start valve on the number 2 engine. What I learned is there are 3 checklists that cover this and the manual start valve checklist has to be imbedded into another checklist to do it. Also; there is no crossbleed checklist which specifically mentions a manual start valve operation. Our discussion with Maintenance was initially around which engine should be started first. Maintenance wanted to start engine number 2 first; but our air start checklist has a warning that states the number 1 engine should be started first. I called the Chief Pilot on this and the Chief Pilot called me back after seeking further guidance. As I expected; we could not deviate from this guidance and we had to start engine number 1 first. This created a problem for Maintenance because they did not want someone between engine number 2 and the fuselage operating the start valve with the number 1 engine running. This limited the maintenance guys egress possibilities. Maintenance supervision looked at the engine danger zone diagram and determined there is a small corridor 90 degrees to left of the center of the engine which would allow maintenance to access and exit the engine start valve area. The maintenance guy would then follow underneath the center line of the fuselage towards the nose to completely exit. So that was the plan. After starting engine #1; we realized the cross bleed start checklist has a warning that mentions no cross bleed starts at the gate. ZZZ does not allow cross bleed starts in the alley around gate XXX so our only option was cross bleed where we were because we needed the maintenance guy to manually open and possibly close the start valve. I decided that because the jet bridge was pulled away and everything was cleared away that we were no longer at the gate. In hindsight; I [think] there were too many out of the ordinary circumstances. The checklists do not account for multiple maintenance discrepancies and our problem involved us embedding the manual start valve checklist into the cross bleed start check while at the gate. Once at cruise; I messaged the Chief Pilot; that this airplane should not fly with both of these maintenance discrepancies. We briefed the outbound pilots at ZZZ2. I do not know if that crew accepted the jet.
Second reporter narrative
MELs were APU Bleed Air Inop and Inoperative Starter Valve. Alone each one is not a particular problem; but combined they made for a convoluted checklist accomplishment process and less than optimum maintenance-flight crew process that was not fully realized until deep into the process. Previous aircrew had refused the aircraft; not for the MELs but for concern there was no down line support for what they were going to have to do at the out station. The Maintenance Technician and the Captain discussed the plan and Maintenance desire was to start the #2 engine first for better egress geometry. However flight manual required starting #1 first. The Chief Pilot and Maintenance Control were all consulted; safety factors analyzed; and the plan was agreed to that as long as ZZZ Maintenance and the Technician were comfortable they would agree to start #1 first. We briefed what we were going to do extensively and asked numerous times to ensure the Technician was completely comfortable. Only after the completion of starting #1 was the full complication of checklist accomplishment realized as we moved to the cross bleed start; exacerbated by ramps location desire for the cross bleed in the area of [gate] XXX. Accomplishing the procedure required us to move back and forth between multiple checklists; and though we tried to be methodical and careful at every step; the non-standard nature of the combination of the two MEL items was overly complicated. In the end engine start was accomplished and the rest of the flight was without incident. Upon arrival we met the outbound Captain and briefed him thoroughly on what had happened and gave him our recommendation that given what we now knew we would have refused the aircraft until at least one of the inoperable systems was repaired.
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Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.