Air carrier flight crew reported one pressurization pack was inoperative when they received an intermittent caution for the second pack so they returned to the departure airport.
Synopsis
Air carrier flight crew reported one pressurization pack was inoperative when they received an intermittent caution for the second pack so they returned to the departure airport.
Narrative
The Captain and I started at the gate as normal and saw we an MEL for the left Pack was inoperative. We went through the MEL procedure and talked about the procedure for a right pack only takeoff and we were restricted to FL250. The rest of the preflight was normal. Once we were number 1 for takeoff we preformed the MEL procedure for a left pack inoperative. We got onto runway XXR and began the takeoff per the SOP's. At rotation we got a master caution light. Since it was after V1 we were go minded. Once we got to about 400 ft I (pilot monitoring) looked and saw that the right pack light was on and we had no pressurization. At the point the Captain and I determined the best course of action was to level off at 3000 ft. Once we got to 3000 ft we [requested priority handling]. At that point we did the after takeoff checklist. After the checklist I went into the QRH for a Pack fail light. Per the QRH we pressed the pack reset light. Once we pressed the button the right pack came back online and we began to pressurize. The problem with the QRH is that it does not talk about what to do if the other pack is MEL'd. Once we got the other pack back online we decided it would be best to return to ZZZ since we were not confident in the right back and the left pack was MEL'ed. We then set up and briefed the ILS runway XY and landed without incident. One factor to the flight was how poorly written the MEL procedure was for the Left pack inoperative. All it says is before and after takeoff and is very vague. Although this was not an issue to our flight we discussed this threat while we were still at the gate. My recommendation is have a better and more concise procedure for that MEL. The biggest factor for this flight was the QRH does not talk about what to do if you lose the other pack while the other was MEL'd. Although this happened right at takeoff so our decision to come back was easy. We felt the QRH was running us down a rabbit hole. My recommendation is to add what to do with a MELed pack into the QRH if you lose the other pack.
Second reporter narrative
Flight ABC took off from runway XX at ZZZ and experienced a MASTER Caution Light on rotation with no corresponding annunciator lights on the Master Caution Annunciator Panel. The Right Pack light was illuminated indicating an overtemperature. After a positive climb rate and gear up; the PF asked the PM to ask ATC to level off at 3;000 feet MSL for a pressurization issue. ATC challenged the request and asked why. Captain told FO to [request priority handling] and request a heading before the LNAV turn on the SID . ATC complied. The PM relayed that we needed 15 minutes before returning to runway XY at ZZZ. Once established on an altitude and heading; the auto pilot was engaged. The Captain remained the PF and called for the After Takeoff Checklist; QRC/QRH Pack Checklist; Non-Routine Landing; Descent and Before Landing Checklist. During the QRH Pack Checklist; the Right Pack light extinguished when it was the TRIP RESET switch was pushed. Although the QRH states that once both PACK lights are extinguished normal operation may continue; the Captain elected to return to ZZZ as a precaution. Dispatch was notified of the divert to ZZZ via ACARS. The Captain informed the Flight Attendants and made a calming PA to the passengers. Once all pertinent checklists were complete; the Flight Crew coordinated with ATC to return to ZZZ. Flight Crew and passenger oxygen masks were not needed. We safely landed below the maximum weight limit; no injuries or aircraft damage. The Captain relayed the issue to the Aircraft Rescue and Firefighting (ARFF) Chief and thanked him for the response. ARFF escorted the Flight Crew to Gate XX. In preparation for the flight; the Captain reviewed the MEL 21-XX-XXX for one inoperable pack; Left side. Procedures on the Bleed Air panel to increase airflow based on the phase of flight were reviewed and executed after engine start. Negative indications on the master caution panel during recall which allowed for operational dispatch. The APU was running during takeoff and landing for additional bleed air.Left pack inoperable leaving crew with only one for flight. QRH procedures do not consider MEL status.Flight Crews should use APU on takeoff and landing for additional bleed air as per MEL 21-XX-XXX to assist with vital air flow for pressurization.Training curriculum should include how to make the right judgment calls when QRH says 'continue normal operation.' In this case; dispatch required one operable air conditioning pack. The Captain decided the risk of the pack failing again at altitude was too high and elected to mitigate the risk; ensuring the safety of the flight crew and passengers on board. Exercise prudent judgement by wielding Captain's authority. This will significantly reduce task saturation and allow crews to be methodical when faced with any non-normal. ATC was much more cooperative and accommodating after [we requested priority handling]. Before they were putting pressure on the crew to expedite requests.Divert as needed to operate at the highest safety margin.
More incidents for this aircraft family →
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.