Air carrier pilots reported an unstable approach; EGWPS warning and the execution of a missed approach.
Synopsis
Air carrier pilots reported an unstable approach; EGWPS warning and the execution of a missed approach.
Narrative
With the autopilot on; at about a 6 mile final to runway XX at ZZZZ; established on the localizer in VFR conditions; VNAV had us above the glide slope. I elected to intervene to catch the glide slope. At first I tried v/s but it altitude captured. I erroneously attempted to select a different mode; but I quickly decided to disengage the autopilot and follow the raw data. We received a EGPWS (Enhanced Ground Proximity Warning System) caution which I acknowledge and said momentary correcting. The Relief Pilot announced unstable approach go around very loudly. As I thought he did not hear me and we were well clear of terrain in VFR conditions; I was a bit startled! With that I was a bit distracted verifying that the flight director was showing incompatible guidance. and I descended thru the glide slope; but then quickly corrected back to the glide slope on raw data. I believe we were stabilized on LOC and GS before 500 feet. I then decided we needed to execute the go around per company policy.
Second reporter narrative
Approach Speed (Vref) - 153 KIASWeather Conditions - Day VMC w/ Light DustWinds - Approx. 200 / 8 KnotsPilot Flying (PF) - CaptainApproaching the airport (ZZZZ) for the ILS Runway XX; the aircraft was stabilized inbound in LOC and VNAV PATH (with G/S armed). It was noted the aircraft; descending on the VNAV PATH; was holding slightly above the glide slope. Approaching ZZZZZ (FAF) and 2;000 MSL ATC altitude clearance; the PF recognized the need to make adjustments to the vertical flight path in order to capture the glide slope. Intending to select a Vertical Speed (V/S) descent in order to do so; the PF mistakenly selected Heading Hold (HDG HLD) and then shortly thereafter; Flight Level Change (FLCH). These actions resulted in the MCP (Mode Control Panel) / FMA (Flight Mode Annunciator) exiting the approach mode logic and commanding heading hold and a level off at 2;000 MSL with associated changes to the FMA and Flight Director.Being aware of this and the importance of capturing the glide slope in a timely manner; the PF disconnected the autopilot and manually attempted to fly the aircraft down to the glide slope. Recognizing the magnitude of the initial nose-down maneuver; I called Watch your Sink Rate which was followed shortly thereafter by the EGPWS (Enhanced Ground Proximity Warning System) callout Sink Rate - several seconds later; while the PF was arresting the sink rate of the aircraft; the automated One Thousand voice aural also activated. At this point; I called Unstable; Go-Around and a Go-Around was executed in accordance with AOM procedures / Company guidance. The crew was given radar vectors for downwind and subsequently cleared for / executed an uneventful and successful ILS approach to Runway XX at ZZZZ.(For information; the nose-down maneuver resulted in an observed maximum descent rate of approximately 2;800 FPM at approximately 1;600 MSL altitude and a maximum displacement of approximately 1 1/2 dots below the glide slope.)
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.