Date: 201910
Local time of day: 1201-1800
Flight conditions: VMC
Light: Daylight
Aircraft: EMB ERJ 170/175 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
Aircraft component: Pneumatic Valve/Bleed Valve
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Communication Breakdown; Time Pressure
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Taxi
Result: Flight Crew Overcame Equipment Problem; General Flight Cancelled / Delayed
Contributing factors: MEL; Company Policy; Aircraft; Procedure
Primary problem: MEL

Narrative: I was going to be pilot flying for this leg; but the Captain had control of the aircraft during the event because it was during taxi. When myself and the crew met the inbound crew in passing on the ramp; they had told us that they received a 'Bleed 1 FAIL' EICAS message in flight (but they were able to clear it after running the QRH procedure) and that the bleed would be deferred. The inbound Captain had been on the phone with Maintenance and deferred the bleed himself before deboarding the aircraft; then; the inbound crew left to the hotel and myself and my crew began regular preflight duties. After I completed the walk around; I boarded the aircraft and began preparing for departure. Scheduled departure time was XA:05Z and we had been approved for a wheels up flow time of XA:15. All preflight; pushback; and engine start operations were conducted without incident. After receiving the takeoff data (which called for an ECS on takeoff) and inputting it into the MCDU; we ran and completed the before taxi check. Just before I was going to call for our taxi clearance; we received an 'ENG REF ECS DISAG' EICAS caution message that surprised us. I looked at the printed takeoff data that I had received and input to ensure that I did it correctly; and then the Captain mentioned something along the lines of 'do we need an ECS off takeoff for the bleed 1 being inoperative? Does the MEL call for that?' and; after thinking about it for a minute and remembering my systems knowledge; I said 'yes I believe we do need to takeoff ECS off'. I told the Captain I would double check the MEL to make sure; meanwhile the Captain then checked the dispatch release and noticed that we never got an amended release for the bleed deferral that the previous inbound Captain had called in to Maintenance. The Captain immediately sent a message to Dispatch asking for an amended release to show the new MEL. The Captain then noticed that the MEL that was written on the placard above the bleed 1 push button was labeled incorrectly; so I looked up the correct number and he sent another ACARS message to dispatch with the correct MEL number. The Captain also fixed the placard so that it was now labeled correctly. Dispatch sent the amended release back to the Captain via ACARS and he was able to physically write the amendment on the release. At this point; the Captain and I knew that we needed to send for new takeoff numbers to show the required ECS off takeoff data. With the distraction of trying to find the correct MEL number and ensuring we got a correct amendment to the release; I never finished looking through MEL 36-XX-XX-XX and I sent for the takeoff numbers again and; while we were waiting; we noticed that we were quickly approaching our required time for takeoff to meet our flow restriction into ZZZ. At this point; the Captain told me to change the ECS setting in the TRS section of the MCDU to 'ECS off' and to leave the remaining ECS ON data that I had already input in order to save time so that; when the actual takeoff data came back; I would be able to quickly reference the numbers to ensure there was no change and we would be able to depart in a timely manner. The Captain and I both initially looked for a way to send specifically for ECS OFF takeoff data; but then realized that there was no way to send for that data specifically (i.e. Dispatch had to know we needed ECS OFF data per the MEL in order for aero data to know we needed it). The Captain called for the before takeoff check and I reached up to turn the APU back on (I had turned it off as a normal part of my after start flow). The 'ENG REF ECS DISAG' message went away and I completed the before takeoff check without any issue. We then received a second set of takeoff data again that called for ECS ON (it was identical to the original data we had received the first time). At this point; it was about XA:13Z and we were about 2 minutes prior to our scheduled departure flow time and the Captain asked me to call for taxi clearance. I once again sent for new takeoff numbers (in hopes of getting ECS OFF numbers) and then Ground Control told us to taxi to Runway 5 and that he would begin working on another flow time because we would no longer be able to depart on time. We began our taxi to Runway 5 and Tower came back and told us they got a slight extension on our departure time and we would be cleared for departure soon. A few moments later; we received takeoff data back (for the third time) which; again; called for an ECS ON takeoff. At this point; Tower instructed us to turn left heading 010 on departure and we were cleared for takeoff on Runway 5. It was now approximately XA:16Z (about 1 minute after our original flow time) and we were worried that if we did not takeoff; we would be significantly delayed into ZZZ. I told the Captain that they sent ECS ON data back to us again and that we didn't have ECS OFF numbers yet and he told me that he thought it was okay to use the data we had and we should depart. We took the runway after completing all other normal procedures and we took off without incident. During climb out above 10;000 ft.; we received a Dispatch message that said something along the lines of 'you took off without the TRS for the MEL restriction'. At this point; we both looked through the MEL and realized that the we had done everything correctly required by the Operations section of MEL 36-XX-XX-XX EXCEPT the one line that says 'ECS OFF TLR DATA - USE'. We began to talk about what had happened on the ground and started wondering why we never got ECS OFF data back. Our thought process was that the Dispatcher may have been rushed to provide the amendment to us (knowing that we had already blocked out and were on the clock to get to ZZZ) and may have sent the amendment without fully understanding what it entailed (this is most likely why we never received ECS OFF takeoff data before departure; despite attempting to do so twice). The Captain and I also discussed the details of what it meant to perform an ECS OFF takeoff. We knew that performing an ECS OFF takeoff meant the engines would not provide any bleed air to the PACKS during takeoff (i.e. the engines would be providing more power on takeoff than it otherwise would if the REF ECS was set to ON). So; we believe that the ECS ON takeoff numbers we used for departure were more conservative than the numbers we may have gotten if we had received ECS OFF takeoff numbers. In other words; the takeoff numbers we used were calculated for an engine performance that was less than what the engine was actually providing for takeoff thrust. There were many lessons that I learned during this flight; as well as many recommendations I would make to myself and other crew members and many things I would have done differently if I could go back and perform this flight again. First; I would do a better job checking the Dispatch paperwork to ensure that it was complete and accurate (had I done this; I most likely would have noticed that the MEL for the bleed 1 deferral was missing before pushback). Second; I would have done a better job recognizing the hazards associated with flow times and I would have understood that; as soon as we began feeling rushed and pressured to depart; we really needed to slow down and accept any delays associated with a change in flow time. Had we taken a step back and accepted an imminent delay; we most likely would have relieved ourselves of the pressure to get off the ground to meet the flow time and would have been able to receive and program the appropriate takeoff numbers prior to departure. Third; I would not have let myself become distracted with trying to find the correct MEL number and ensuring we got a correct amendment to the release. Had I not become distracted and had; instead; told the Captain that I needed to focus on one thing at a time; I most likely would have finished reading the MEL and seen that we specifically needed to use ECS OFFtakeoff numbers before we departed. Fourth; when Tower cleared us for departure before we had received our ECS OFF numbers and the Captain said that he believed it was okay to takeoff; I should have told both the Captain and ATC that I was not ready to depart and that we would need a few more minutes on the ground. This would have allowed me to express my confusion and concern about taking off without the ECS OFF numbers and would have provided the Captain and I the opportunity to do what we needed to before we took off.




Synopsis: EMB-175 First Officer reported a miscommunication with Dispatch resulted in departure out of compliance with the MEL.