Date: 202102
Local time of day: 1801-2400
Location: ZZZZ.ARTCC, FO
Weather elements / visibility: Icing; Rain
Aircraft: B767-300 and 300 ER
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Descent
Reporter organization: Air Carrier
Reporter function: Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Human-Machine Interface; Situational Awareness; Workload; Distraction; Communication Breakdown
Second reporter function: First Officer; Pilot Not Flying
Anomaly: Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Automation Air Traffic Control; Person Air Traffic Control
When detected: In-flight
Result: Flight Crew Returned To Clearance
Contributing factors: Human Factors; Weather; Procedure
Primary problem: Human Factors

Narrative: Arriving into ZZZ the altimeter setting was showing 0996 mb; so during our arrival brief we covered the VNAV limitation for altimeters lower than 29.70/1006 and put special emphasis on using FLCH (Flight Level Change) when transitioning. Transition level was FL070. ATC began descending us in small steps; they gave us a descend to FL070 but when we were passing FL080 they gave us a descend to 6;000 ft. then further lower to 5;000 ft.; during those step downs I missed switching the altimeter setting to the local 0996mb. Then when we leveled at 5;000 ft. ATC verified the altimeter setting stating that we were 400 ft. lower than we should have. I immediately realized my mistake; set the correct altimeter setting; took corrective action and called for the approach checklist. Since the airplane wasn't reacting as fast as I wanted; I disconnected the auto pilot; corrected the altitude and continued manual flying all the way until we landed. There is no excuse for missing an altimeter setting during transition. There were many factors/distractions that took place for this to happen and they all came pretty close together: long duty day; our bells to the flight attendants; re-route to a point not in our route; use of wing and Engine anti-ice; heavy rain during descent so continuous ignition was set; multiple small step downs from ATC; VNAV limitation; all of them occurring often simultaneously. We; as crew; came together and managed all threats that were thrown at us as best we could to bring the airplane safely to the ground.I will; from now on; better prioritize on the stuff that I delegate and ask my crew to keep an eye on me and remind me of things that could make us incur a deviation like this one. Even though we all had our hands full; I should have asked someone for some sort of reminder about the transition level.


Second narrative: At the conclusion of a long duty day and the second flight leg of the day; I was PM (Pilot Monitoring) en-route. This was my second leg as PM (6th leg as flight crew) in an international theater in nearly 3 years. Prior to descent and during the approach briefing as well as once the relief pilots entered the cockpit; we discussed the lower altimeter setting of 0996mb and the associated procedure per Company limitations from not using VNAV when transitioning from QNH (Height Above Sea Level) to QNE or QNE to QNH when below 1006mb. We felt very prepared for the arrival and descent into ZZZ. The transition altitude of 7;000 ft. was also briefed however as we proceeded; we encountered winter weather requiring extra vigilance (icing conditions and heavy precipitation). ATC descended us in multiple small increments below 10;000 ft. but the last prior to this event was a descent to 5;000 ft. With the added attention to the weather and ensuring proper use of FLCH instead of VNAV during what should have been the transition; both the pilot flying; and the pilot monitoring did not switch the altimeters at the proper time to the local setting of 0996mb. Upon level-off at 5;000 ft.; ATC came over the radio to verify local altimeter of 996mb and stating the observation of being 400 ft. low. I quickly realized my altimeter was incorrect and took corrective action and confirmed the pilot flying did so as well both with the altimeter and the flight path. One of the observer pilots also confirmed and stated the MSA for situational awareness. The pilot flying disconnected the auto pilot and continued to intercept the localizer path while returning to the cleared altitude. The aircraft was hand flown to landing with no further incident.Multiple links in the chain led up to this event and while we thought we had sufficiently briefed the several unique environments (low altimeter/Company limitation; winter weather) we also were distracted by being vectored to a point not on an arrival or the approach expected. It only goes to show that even with the best preparation and briefing that events can change and compound quickly and while attention to detail is most crucial during all phases of flight; extra vigilance is needed for approach and arrival; especially in areas that have not been flown to in recent months or years. Ultimately; the crew worked together to safely return the aircraft to the desired state and ensured a lesson learned for the future when operating in areas with differing transition altitudes.


Synopsis: Flight Crew flying 767-300 aircraft reported not resetting altimeter during descent.