Air carrier flight crew reported descending below charted altitude on approach to LIH; citing workload and improper MCDU programming as contributing.
Synopsis
Air carrier flight crew reported descending below charted altitude on approach to LIH; citing workload and improper MCDU programming as contributing.
Narrative
I was cleared to fix NAPUA at 3000 ft; then the ILS 35 at Lihue. We were expecting the visual so a late change to the Multipurpose Control Display Unit (MCDU) was made; though the ILS was loaded but fixes not displayed in MCDU. I entered 3;000 ft. as a constraint to NAPUA then set the altitude in the autopilot to 1900 ft. as I was cleared the ILS and 1900 ft. is the FAF altitude. However; the fixes on the ILS were not showing up in the MCDU so I manually entered in the IAP of MORKE to fly to after NAPUA. I did not enter 3000 ft. as a constraint at MORKE which is the IAP altitude. Thus; due to this oversight we descended to 1900 ft. at the IAP. By the time I noticed this were were VMC and established on the localizer so I proceeded to the FAF; intercepted the glide slope and landed uneventfully.Cause: Lack of knowledge as to how to get the ILS fixes to show up when I had the ILS selected; not entering in the IAP altitude constraint as an oversight due to task saturation.Suggestions: Ensure all fixes displayed in MCDU prior to approach; attempt to reload the approach sooner.
Second reporter narrative
We descended prematurely below the 3000 ft. altitude at MORKE. The ILS35 approach was previously entered in the Multipurpose Control Display Unit (MCDU); but HCF cleared us direct to NAPUA; direct LIH. This routing was entered in the MCDU. Approaching NAPUA; HCF cleared us for the ILS35. The approach was reconnected; but incorrectly without the 3000 ft. altitude at MORKE. The next lower altitude was entered in and the error was recognized in the descent passing MORKE.Cause: This was my first time into LIH. We briefed for a visual backed up by the ILS35. I had an expectation for ATC's typical vectors and altitudes to intercept the approach or a visual approach clearance. As a result; I did not expect to be cleared for the approach via the NAPUA-MORKE transition.Suggestions: This appears to be a question of technique. In this case; expecting to fly the approach as a visual back up; we could have left the approach strung from NAPUA in the MCDU to avoid entering/programming the approach at the last minute.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.