Flight Crew Air Transport Pilot (ATP)
Communication Breakdown; Human-Machine Interface
ATC Issue All Types; Deviation - Speed All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Unstabilized Approach; Inflight Event / Encounter Weather / Turbulence
Flight Crew Returned To Clearance
Human Factors
We were descending via the SEAVU2 arrival into LAX. On the way in; we received several instructions from ATC intended to delay our arrival; including speed changes and off course delay vectors. Other aircraft in the area were told to 'make a right 360' and 'Approach isn't ready for you yet.' The First Officer (FO) was the Pilot Flying and had set a hard altitude of 12000 at SEAVU rather than the programmed between 12000 and 14000. We were very busy and when he made the suggestion I agreed because the FMS was projecting SEAVU at 14000 and the winds were shifting wildly in both speed and direction. Aiming for the bottom of the altitude window was a good idea; because it would give us some leeway in case the wind shifted and we were unable to make the 14000 restriction. I didn't have time to clarify with the FO at the time if this was his intention; but I thought it was a good idea considering the circumstances. We had been descending at 270; as assigned by LAX center; and when we checked on with SoCal approach we were slowed to 250. This produced an idle power descent and while it was continuous light; occasional moderate all the way down; the aircraft was pretty much staying on speed. I looked away to change my LIDO chart from the SEAVU2 arrival to the ILS 25L and when I looked back the aircraft had increased speed to 270 and was trending higher. I said; 'Airspeed!' and the FO promptly reached for the thrust levers and the spoilers in an effort to slow back to our assigned 250. The SoCal approach controller asked a preceding aircraft to 'say speed' and he replied '250' and then the controller asked us to say our speed and I responded '270; slowing back to 250. We had some shifting wind and are slowing down now.' The controller asked us to slow to 230; which we did; and then issued 230 knot restrictions to several other aircraft. In an effort to slow down; the FO changed the vertical mode to VS and arrested the descent in order to slow down. I think at one point I saw a positive vertical speed selected but I'm not sure if we ever actually gained any altitude. At this point it became clear that we were operating on two different plans; and with all the turbulence communicating was difficult. I told the FO to continue descending and started to process where we were vertically on the arrival; with respect to the altitude limits since we had 1900 set in the altitude pre-selector and were off of VNAV. After a few moments we got everything sorted out and continued to land. Just outside the FAF; tower asked if we could accept a sidestep to 25R. I had anticipated this; and had calculated performance numbers for 25R so I knew we could accept it. I asked the FO if he was comfortable taking the sidestep and he said yes; so he disconnected the autopilot and lined up on 25R. We were a little slow configuring and I wasn't sure we'd be stable; but we were configured; on speed; and lined up on the 25R centerline at 1000 feet AGL. It was about this time that tower gave us the localizer frequency for 25R and I manually input it into each side and re-armed the approach mode. When the glideslope came in; we were low and got a 'GLIDESPOPE! GLIDESLOPE!' caution and I announced to the FO that he was low. It was VMC and we were in position to land so I wasn't too concerned. In the debrief we talked extensively about what we were both doing. The FO was confused by the 'GLIDESLOPE' message because he didn't realize I had tuned and armed the 25R frequency; which I assumed he would have expected me to have done. He explained that he was just flying a normal visual approach and had picked a spot on the runway as an aim point and was using the FPV to create his own 3 degree reference glide path (which I thought was very clever for someone with only a couple hundred hours in the aircraft). We talked about the confusion on the arrival; starting with the speed deviation. I am confident that nothing we did caused the aircraft to increase in speed. It was just ashift in wind. If the FO hadn't programmed SEAVU at 12000; we would have never made the restriction at 14000 (if we'd had the same increase in speed) because of the shifting winds and reduced descent speed. The FO told me that he was aware of the next altitude; which was at or above 10000; and that since we were already below 14000 (having made the restriction at SEAVU early) when the aircraft sped up; he was just going to manage the descent manually until back on the profile. We talked about how we both could have communicated our actions and intentions better; but that given the circumstances there was little time to talk and in the end it all worked out OK.
Regional Jet crew on SEAVU2 arrival to LAX with speed reduction given a late change to Runway 25R descended below the glideslope on final.