Date: 201902
Aircraft: B737 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Human factors: Distraction; Situational Awareness
Second reporter function: First Officer; Pilot Not Flying
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Aircraft In Service At Gate
Result: General None Reported / Taken
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: During post landing and taxi in; I commanded the shutdown of the number 2 engine. Upon reaching the gate and setting the parking brake; I said 'Brakes set; pressure normal. Shut down number 1.' I saw; out of the corner of my eye; the First Officer move a start lever. I assumed the First Officer shutdown the engine so I continued with my parking flow and made a short call to Maintenance to report a write up. I then called for the Parking Checklist. The second step on the checklist is checking that the start levers are cutoff. I found both start levers in the run position with the number 1 engine still running. I immediately positioned both start levers to cutoff shutting down the number 1 engine as I was concerned about the safety of ground personnel. The number 2 engine was not running at the time. The First Officer had mistakenly return the number 2 start lever to run instead of shutting down the number 1 engine. No injuries occurred. Upon debriefing the event; the First Officer said he understood my command but just made a mistake.


Second narrative: Upon taxi to ramp after normal landing; Captain requested First Officer shutdown #2 Engine after three minutes timing. Continued to parking via normal procedures. After parking brake set; Captain requested to shut down number one engine. First Officer mistakenly placed number TWO start lever to Idle instead of number ONE to cut off. (Levers matched in wrong position). Neither First Officer nor Captain monitored FF/EGT [Fuel Flow/Exhaust Gas temperature] for shut down as per procedures. While First Officer continued with engine shut down flow; Captain became involved with contacting Maintenance to report a cabin discrepancy. Estimate 60 to 90 seconds lapsed before Captain was ready to run the Parking Checklist and realized that the engine was still running with anti-collision light off. Both start levers returned to CUTOFF at this time. Number one engine shut down without further incident. Threat error debriefed. First Officer reported sensing unusual 'muscle memory' sensation subsequent to erroneous shut down and conducting flows (initially hesitated by placing lights to on/down vs off/up position). Captain acknowledged he should have monitored shutdown and completed Parking Checklist before contacting Maintenance. No other causal factors or mitigating circumstances could be identified for this procedural error.


Synopsis: B737 flight crew reported failing to properly shut down engines after gate arrival; creating a hazard for ground personnel.