Date: 202010
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
Aircraft component: INS / IRS / IRU
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Human factors: Distraction; Fatigue; Training / Qualification
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Passenger Misconduct
Detector: Person Flight Crew
When detected: Aircraft In Service At Gate
Result: General None Reported / Taken
Contributing factors: Aircraft; Environment - Non Weather Related; Human Factors
Primary problem: Human Factors

Narrative: I made an error in not verifying that all 3 ADIRS were aligned before departure after having the preflight flow interrupted by the passenger disturbance at the gate. I tried to be deliberate and methodical in reviewing the manual after discovering the error before performing the alignment and thought I had found the only pertinent caution; the flaps/slats. The format of the manual made it appear to me that the section was complete on page X. Only suggestion would be to keep all cautions and warnings for a given section grouped together in the text; instead of having one at the start of the section and another at the end of the section (in this case on the next page).The First Officer (FO) and I discussed the threats and errors that occurred on this morning and the opportunities that I missed to capture those errors. We additionally thoroughly reviewed the system. I take away a number of lessons learned from this morning and will be more vigilant when I recognize when my habit patterns are interrupted.Other potential considerations:My FO and I had briefed the entire trip that he was low time (just over 100 hours) and I had not flown in 5 weeks.  While I felt rested and alert; this was day 4 of a 23 hour trip with all early morning shows which may have also contributed to a decreased capacity.  My cockpit preparation flow was interrupted when a passenger; who had refused to pay for his carry-on bag; breached the gate in ZZZ and caused a disturbance at the forward door. I got out of my seat to see what was going on and prepare to close the door should things escalate. When I returned; I thought I had finished my flow completely but after pushback and engine start realized I had not turned on IRS3 when we got an ADR3 fault caution message.Knowing that there were warnings and conditions about aligning IRS's outside of the normal preflight I opened page X which has the ADIRS preflight information. The caution on that page said to make sure the flaps and slats were retracted before aligning; which was confirmed before I turned on IRS3. Since there was a GPS outage in our area; and we had moved in the pushback after aligning IRS1 and IRS2 I also decided to do another full alignment of those. When I selected all of the ADIRS off we got a master warning for the ADIRS 1+2+3 fail and other cautions which all resolved after I turned them on to align again. Knowing we had gotten out of our normal flow; and recognizing that I had gotten distracted with gate issue; during the alignment the FO and I went through the preflight items and reviewed our previous work to confirm we had not missed anything else. After the alignment was complete and all systems normal we departed for an otherwise uneventful flight. Once in cruise; I went back to review the manual and found on the next page Y a continuation of the ADIRS section with an additional second bullet point; one that said not to align the ADIRS with the engines running.




Synopsis: Air carrier Captain reported making a procedural error during preflight and cited a distraction and lack of recent flying as contributing factors.