Medium Large Transport
Flight Crew Air Transport Pilot (ATP)
Communication Breakdown; Confusion; Distraction; Time Pressure; Workload
ATC Issue All Types; Deviation - Altitude Crossing Restriction Not Met; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued Advisory / Alert; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Aircraft; Airspace Structure; Chart Or Publication; Procedure
Not sure if we met crossing restriction MEA or not. The reason was because we had two route changes in the FMC and there is overlap between the departure procedure and the instrument approach procedure where the departure procedure does not have the waypoint and the approach procedure has it and we neglected to get waypoint in the route with the last change. The SID does not have waypoint ZZZZ1 Intersection between ZZZZZ Intersection and ZZZ VOR and has a higher MEA on that segment. The VOR Approach to ZZZ1 has ZZZZ1 Intersection with 4500 feet MEA before and 4000 feet MEA after. We were thinking correctly on our descent on that segment but didn't have the waypoint in the FMC to verify that we stayed above 4500 feet before that spot so we may have clipped the corner and went below 4500 feet by 100 feet - 200 feet within a mile or so of the waypoint. How this happened: on the ground at ZZZ we were filed on the SID. We requested an amendment to do [two different SIDs]. Both of these were declined by ATC due to poor communication capabilities in the area. So we were assigned as filed [the original SID] climb to 6000 feet. I was worried about getting down quick enough from 6000 feet especially if we had com problems and we couldn't get a clearance until late. This proved to be unfounded but it was on my mind. So; the FMC was loaded that way which leaves out ZZZZ1 Intersection. When airborne we had delay getting a hold of center but finally did approaching ZZZZZ Intersection. He gave us a 'cruise 6000 feet' clearance. In the communication following we wanted to verify what that allowed us to do since I hadn't used that terminology in a while. I think the controller sensed our confusion and stated that it meant that we could 'descend to 4000 feet our discretion and commence the approach'. So we set 4000 feet in the MCP and began descent. We were past ZZZZZ Intersection at this time and were thinking we could descend to 4000 feet unrestricted before ZZZ VOR because that ZZZZ1 Intersection wasn't in the box; and from what the controller said about descent to 4000 feet our discretion. I think he should have said we can initiate descent our discretion to commence approach without saying 4000 feet. It was our fault but the way he said it with the time crunch made us miss the ZZZZ1 Intersection error. We reached 4000 feet a few miles prior to ZZZ VOR. After ZZZ VOR; the controller informed us that he saw an altitude readout of 4000 feet and that segment was a 4500 feet MEA referring to the segment where we were when we initiated descent. That is true but it also allows 4000 feet after ZZZZ1 Intersection and our descent rate was targeted to reach 4000 feet just before ZZZ VOR so I know that we were not at 4000 feet before ZZZZ1 Intersection but we may have been a little below 4500 feet. Contributing to this was my hesitation about understanding the cruise clearance; the poor communication capability of ATC in the area necessitating the higher altitude and a late clearance to descend; and the oversight of not getting ZZZZ1 Intersection back in the FMC after the last change which occurred airborne. Remember that we were airborne only 15 minutes so all of this occurred within a window of just 3-4 minutes.I should have reverified the route after the descent clearance was received before initiating descent. During the descent on that segment were both aware of the nearest terrain; had briefed it; were monitoring the EGPWS; could see glimpses of the ground and water below; and at no time were we worried about terrain separation as a safety factor.
A Medium Large Transport Flight Crew on a twelve minute flight entered a SID and then an arrival at their destination which omitted a waypoint which would have aided them in detecting the MEA on their arrival. They briefly descended below the MEA. ATC advised them of their error and they continued on to their destination.