Date: 201710
Local time of day: 0001-0600
Location: ZZZ.Airport, US
Light: Daylight
Aircraft: B737 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
ATC / advisory: Ground ZZZ
Aircraft component: Pneumatic Valve/Bleed Valve
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Distraction
Second reporter function: Pilot Not Flying; First Officer
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Taxi
Result: Flight Crew Returned To Gate
Contributing factors: Procedure; Human Factors; Aircraft
Primary problem: Procedure

Narrative: It was the second day ever to fly together and the first flight for both of us in the MAX. Normal pushback. We received Impending Hot Start on Number 2 engine with auto shutdown. My attention was totally outside the aircraft as I was in the process of clearing the Ground Crew off. My attention was drawn back inside to see the white flashing box around the EGT with the motor rolling back. At the time; the F/O (First Officer) had no idea what may have caused it; so we ran appropriate QRH items for a suspected malfunction; started number 1 engine; and taxied back to the gate; making a logbook write-up; and calling Maintenance. Having time to discuss what may have happened; looking through numerous publication sources; and sleeping on it; the F/O is now sure that he prematurely isolated/ventilated just momentarily; but long enough to steal the air source causing an incomplete and auto aborted start. Despite being patient and pre-briefing that we would not rush our first MAX experience in any way; anxiousness over the newness and the longer start process must have still affected our pacing. The Isolation switch to Isolate and the Pack switch to ON before engine rollback obviously caused the engine to shut down.More training would be great; and hands-on training would certainly have been beneficial. Still; we felt prepared; but the hype of the new aircraft with the unfamiliar pacing caused an unfortunate situation.


Second narrative: It was a normal pushback. The Captain indicated to start number 2 engine. I followed procedures for start and everything appeared normal. During the end of the start; I thought I heard the Captain say 'Start number 1.' I was looking at the number 2 engine EGT and it had appeared to peak so I reached up and selected isolation valve CLOSED and right pack ON. I then reached over to start number 1.When I glanced down at the number 2 EGT I realized there was still a red tick mark so I did not start number 1. Within a second or two; I noticed the number 2 engine EGT box white and flash and the Oil Pressure light illuminate and the engine rolled back. We accomplished the Aborted Start Checklist; started the number 1 engine and taxied to Gate XX.When I heard start number 1; I should have verified that a full rollback had indeed taken place prior to moving my hand away from the start lever. Instead since it appeared the temperature had peaked I made an assumption that it was incorrect. Obviously; this was a new variant so out of an abundance of caution we went back to the gate instead of attempting another start. In hindsight I should have also voiced turning on the pack more loudly to Maintenance; but at the time we were not really sure what caused the rollback. There is already a note in the Aircraft Operating Manual regarding pack usage during start. This was just a pure mistake on my part in turning on the switch to early.


Synopsis: B737 Max flight crew reported that an Auto Shutdown of the Number Two engine on engine start was probably due to the First Officer activating the Isolation switch and the Pack switch during the start.