B737-800 flight crew reported communications issues resulted in a descent below assigned altitude during the approach. Flight crew climbed up to correct altitude and continued the approach to landing.
Synopsis
B737-800 flight crew reported communications issues resulted in a descent below assigned altitude during the approach. Flight crew climbed up to correct altitude and continued the approach to landing.
Narrative
ZZZZZ 1B arrival into ZZZZZ. Received clearance 'descent to FL250 at ZZZZZ.' Complied. After ZZZZZ; received clearance 'descend via ZZZZZ 1B; maintain 14 thousand;' We started our VNAV path descend. Passing ZZZZ1; we were given vectors; heading 070 while still descending to 14K. To the northwest of ZZZZ2; we were given clearance 'direct to ZZZZ3 and descent to 10 thousand (or descend and maintain 10 thousand; definitely not DESCEND VIA'). LNAV and VNAVing to ZZZZ3; noticed we are not descending below 14K due to the altitude restrictions in the FMS; and knowing we weren't given descend via for the 10K; I either V/S or LVL CHGed to start descending to 10K. Passing 11.5K; VFR; it seemed odd that they would want us that much lower than published. We asked approach to confirm descend to 10K. ATC responded with we're below the altitude on the arrival; I immediately dialed in something higher in the altitude window and started a climb. At the same time we received CAUTION TERRAIN; ATC came back and said we're given a descend via to 10K and now to climb and maintain 12 thousand. We climbed back up to 12K and completed the arrival and approach. Being a domestic pilot my entire time at [Company]; pretty much all of it in ZZZ. This might be the second time I've been to ZZZZ with the previous occasion probably over 6 years ago. Only ever flew into [Country] a handful of times and no [Continent]. I made sure I read all the airport familiarization pages; all the Jepp pages; all the [Country] info in the FOM. And was extremely vigilant regarding 'direct to vs direct' and 'descend via and descend to' clearances. Those were the key words I was listening for. Me and the Captain both agree and the second clearance did not include descend via. I do believe my lack of outside of US experience played a role. I trusted foreign ATC and thought the that low descent was common local procedure. In training and all the distance learning modules; we get hammered on the difference between DIRECT TO and DIRECT. I don't recall as much of an emphasis on DESCEND VIA vs DESCEND UNRESTRICTED (which is official ICAO phraseology on an arrival) and DESCEND TO/DESCEND AND MAINTAIN; which is a FAA phraseology for US arrivals meaning to descend unrestricted. I believe these points should be emphasized in future training modules. In regards to ZZZZ ATC; in my opinion they should only use 2 descent terminologies on arrivals with altitude restrictions. Either DESCEND VIA or DESCEND UNRESTRICTED. Using a DESCEND AND MAINTAIN or DESCEND TO clearance on an arrival with altitude restrictions; from what I can tell is non-standard per our FOM and should not be used.
Second reporter narrative
CLEARANCE......Descending Via ZZZZZ 1B except maintain 14;000. Just after ZZZZZ vectored off the STAR to the east for spacing and given a descent to 10;000 ft. with multiple speed changes. Approaching 10;000 ft. in VMC conditions I queried the Controller about our altitude he said we should be at 14;000 ft. descending via. We were on vectors. We immediately initiated a climb to 14;000 ft. and as per his request leveled at 12;000 ft. We were cleared direct to ZZZZ3 and were told to rejoin the STAR. We landed XXL I believe there was a freq change to a new controller who forgot about us. He made no mention of our altitude until I asked him to confirm. There was also no mention of rejoining the STAR.Remain on the STAR/SID to the max extent possible.
More incidents for this aircraft family →
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.