Date: 202002
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Night
Aircraft: B737-900
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
Aircraft component: Aircraft Auto Temperature System
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; First Officer
Reporter qualification: Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Human factors: Troubleshooting; Workload; Communication Breakdown; Confusion; Fatigue; Time Pressure
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Maintenance
Detector: Person Flight Crew
When detected: Pre-flight
Result: General Maintenance Action; General Flight Cancelled / Delayed
Contributing factors: Aircraft; Procedure; Staffing; MEL; Human Factors
Primary problem: Procedure

Narrative: I was scheduled to fly aircraft from ZZZ-ZZZ1. Upon pulling the paperwork in [our EFBs]; we saw 4 MELs (21-XX (both packs); 31-XX; and 21-XX; I believe). As we arrived to the aircraft to begin pre-flighting; we saw all of the MEL stickers and lots of lights illuminated. At some point we noticed that the Right PACK light was not extinguishing after the MASTER CAUTION reset was performed. When we selected the temperature display; we saw the right pack temp was 80 degrees C and climbing. So we turned off the right pack. This seemed odd so the CA (Captain) called maintenance control who told us that this was normal as the RAM air valves were slightly closed and the pack wasn't getting any airflow since were on the ground. Except the left pack had the same write ups and was indicating about 12 degrees C. The CA called [Flight Operations and Dispatch] and relayed our situation (meanwhile we're completely boarded and awaiting close out/pushback at this time). [Flight Operations and Dispatch] initially seemed to think the PACK light was related to our multiple MEL situation; until we realized and thus pointed out; that for all the current MELs; the PACK lights may illuminate upon MASTER CAUTION recall; but should then both extinguish after MASTER CAUTION reset. Around this time we realized if we didn't have all these MELs and showed up to a jet with a PACK light illuminated and pack temp exceeding 80 degrees C; we would write it up; so that's what we ended up doing. The mechanic came out to work on the aircraft while crew scheduling called to ask if we'd accept a duty day extension as our show time was XA:30 acclimated and we weren't going to make our original arrival time. We accepted the extension; meanwhile the mechanic had to call in a mechanic from ZZZ2; then scheduling opted to put us back in rest. We ended up flying the aircraft out 14 hours later than scheduled with the Right pack MEL'd out. 21-XX.It seems with multiple MELs on an aircraft; crews are not getting set up for success. This would have been extremely easy to miss as we were busy juggling several calls with different entities; looking over unpressurized takeoff procedures due to the MEL and wet runway. There was an animal in the cargo hold that would have needed to be removed if we were going to get the pack MEL'd in time for our original flight. All after a XX:30 wake up. I'm glad we took the safety pause and stepped back to see if it made sense; because it didn't. Recommendations: keep MELs to a minimum; avoid building fatiguing pairings.




Synopsis: B737 First Officer reported departing after a 14 hour maintenance delay due to multiple MEL issues.