Air carrier crew reported an altitude deviation on final approach resulting in the aircraft being below the glide path and below the maneuvering speed. The crew recovered airspeed and glide path then landed.
Synopsis
Air carrier crew reported an altitude deviation on final approach resulting in the aircraft being below the glide path and below the maneuvering speed. The crew recovered airspeed and glide path then landed.
Narrative
Approaching JWARD on the DSNEE arrival speed was 220 so I told PF he should be 190 at JWARD. PF dialed speed to 190. At about the same time we got switched over to third SoCal controller who gave us a heading and descent to 6300 feet. We asked about getting the RNAV approach clearance just as we had the previous two controllers. He commented about wishing the previous controller had just given it to us then he said we could go direct BONVY or DEKRT for for RNAV or just do a visual approach. We were in lvl change with speed brakes out. We opted to go to BONVY so I did the direct to engaged LNAV set/ confirmed 1400 feet for the FAF altitude not realizing we were no longer in VNAV. At approximately 5000 feet I realized we were low and called it out. PF disconnected the autopilot to immediately level off. I called out that speed brakes were still out then noticed we were appoximately 20-25 knots below clean maneuvering speed which I called out. PF pushed up the thrust levers. I also said we need flaps 5 and we extended flaps to 5. VNAV was reengaged; autopilot was reengaged and the rest of the approach and landing were uneventful. A contributing factor was the very late frequency change and getting a late unexpected clearance. Also contributing was lack of mode awareness and automation management.
Second reporter narrative
From DSNEE to JWARD I was late to recognize that the autopilot did not slow me from 220 to 190 as I expected; so I opened the speed window to set 190 and used boards to help slow down; simultaneously was cleared from 8000 to 6300 and I opted to use LVL CHG to descend but I didn't not call for any flaps yet as I should have. Since we had not yet received an approach clearance; we began a turn the west and shortly thereafter we were cleared direct BNVOY to 5000; cleared for the RNAV Z 20R. PM selected 1400 for the approach clearance and I was still in level change and failed to ask for VNAV to be reengaged.PM pointed out that we were below 5000; so I disconnected the A/P and began to level off and initiate a slight climb to meet the restriction at BNVOY. I got slow approx 20-25 knots below clean maneuvering speed. PM pointed verbalized the speed; I corrected the speed and flap setting to remedy the situation; reengaged the autopilot and flew the remainder of the approach stabilized. Some factors may include fatigue from early report time; some confusion about our actual approach clearance and how late it was issued; and a loss of SA; lack of mode awareness due to low flight time and first flight after nearly 3 weeks.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.