Date: 202009
Local time of day: 0001-0600
Location: ZZZ.TRACON, US
Aircraft: B767-200
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Takeoff / Launch
Airspace: Class B ZZZ
ATC / advisory: TRACON ZZZ
Aircraft component: Autothrottle/Speed Control
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Human factors: Distraction; Situational Awareness; Time Pressure; Workload
Second reporter function: First Officer
Anomaly: Aircraft Equipment Problem Less Severe; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Detector: Person Air Traffic Control
When detected: In-flight
Result: Flight Crew Returned To Clearance; Flight Crew Became Reoriented
Contributing factors: Procedure; Aircraft; Human Factors; MEL; Manuals
Primary problem: Human Factors

Narrative: We got called out to do a flight off of Reserve. When we showed to the airplane; we were told that our paperwork was not correct for our flight. Maintenance had added an MEL that removed the Thrust Computer with autothrottles. This meant that we had to do all of the climb data off of charts; use a supplementary procedure for takeoff and we could not do any RNAV1 departure procedures. We got our clearance with the departure with a climb straight out to .6 DME fix off of the LOC or a waypoint then a left turn northwest.  I put the 1.0 DME fix from the LOC in the fix page and the FO (First Officer) put the waypoint name. We then put the [departure] into the FMS to back up the non RNAV SID. The FMS built the departure and we used the FMS for a non-RNAV as we normally would. We briefed the departure as normal. Upon reaching the runway we briefed it again; and then briefed the non-normal takeoff procedure. When we departed out of habit the PF (Pilot Flying) asked for LNAV; it was selected; and the plane commanded a turn to the right as the position had not updated. Just into the turn I started to question why we were turning in the opposite direction of the SID. The tower told us to turn to the outbound heading. We complied; no further issues with the SID.I believe that the root cause of this is a combination of things. The very complex MEL that we were given at the last minute; combined with the non-normal takeoff; and an unfamiliar departure procedure. We were focused on making sure that we had the plane setup correctly to fly that the SID fell in priority.I feel that we completed the entire preflight using SOP; but when it came down to task saturation we both reverted back to 'what we normally do' and relied on the FMS with LNAV on the departure and this caused us to turn in the wrong direction. This could have been mitigated by not using the FMS in any way for the departure; which I think is the intent of the supplementary procedure. My opinion is that we should add into the procedure that use of the FMS for takeoff is prohibited until such a point that the plane will update location.  The other way we could have mitigated this is simply by asking for a heading after takeoff.


Second narrative: I was called to do a flight while on reserve. I arrived a little early at the facility. I printed out the paperwork and waited for the Captain to arrive. We met up and went out to the airplane. When we got to the airplane we were asked what revision we had and I told the Rep we had Revision 5 she said that we needed revision 10. We waited for new paperwork and at that time we found out about a very complex MEL to the plane. This MEL required a lot of pre planning we read the MEL and one of the items was RNAV 1 prohibited along with a lot of calculations from charts. We completed everything and loaded the FMS. Our original route was direct ZZZZZ off Runway XXC. Upon getting our clearance we were given [a] departure. I looked at the departure and noticed I was not an RNAV1 and looked at the instructions. There was an insert depicting what to do. It was at 004 heading to .6 [DME] which is a waypoint ZZZZZ1 then a left turn to 330. I put ZZZZZ1 in the fix page and the captain put .6 [DME] in the second fix page. All for reference to back up when to turn. After that I changed to SID in the FMS and the FMS generated the ZZZZZ1 fix in the waypoints. I then thought I could just fly it in LNAV at 400 ft. like normal since it was in the FMS. In the climb out ATC asked why we were turning that way and gave us heading to rejoin the SID. The flight continued with no further incident The cause of the problem in my opinion was a lot things happening at the same time combined with a very complex MEL that was my first time having to deal with. A last minute change a non-normal flight condition which made the departure a very busy time contributed to the mistake. I think this all could have been mitigated if I stuck to the original plan and flew the SID using the original heading and not relying on the FMS.


Synopsis: Air Carrier flight crew reported deviating from clearance on departure.