B787 Dreamliner Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 220; Flight Crew Total 8604; Flight Crew Type 425
Distraction; Confusion; Training / Qualification
Aircraft Equipment Problem Less Severe; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued Advisory / Alert; Flight Crew Overcame Equipment Problem; Flight Crew Returned To Clearance
Aircraft; Company Policy; Human Factors
During pre-flight planning and continuing into our cockpit briefing all 4 of us reviewed the 787 Flight Manual Revision issued earlier in the week as well as the FOM revision. We discussed in detail the change specified in the NORMALS page concerning the need to manually enter Vref 30+80/ 3000 ft AGL on VNAV CLB LS page 4L for a (Noise Abatement Departure Procedure 2) NADP-2 departure. As we taxied-out the FO (First Officer) typed into 4L: 252/3128 and I specifically said as he was entering the data; 'let me see what you are doing' and independently verified the entries. I know for a fact that it was done correctly per the FM! However; no person on the crew truly could understand the reason for the SOP (Standard Operating Procedure) change but; we dutifully complied with it anyway. ('training by bulletin' as it has become known on the line). The FMA's (Flight Mode Annunciation) were called-out by the PF (Captain) per the new SOP's as the TOGA (Take Off Go Around) switch was engaged. At 50 ft LNAV engaged and was called-out as; 'LNAV'. At 400 ft. VNAV engaged and was called-out as; 'VNAV SPD'. At 800 ft the speed bug advanced to the flap speed minus 5Kts and the FD command bug indicated a pitch reduction to accelerate. We continued to accelerate to 252 KIAS as that was what we had entered on the VNAV CLB page 4L and continued the climb. However at 3000 ft AGL VNAV malfunctioned and commanded a speed of 322 KIAS followed immediately by an FMC ALERT Message: 'UNABLE NEXT ALTITUDE' - Which was LADYJ at 8000 (LADYJ 1 KLAX). The Flight Director commanded a further pitch reduction for the speed increase. The FO went immediately heads-down and pulled-up the VNAV CLB PAGE in the FMC and started typing trying to override the 322 KTS at 2L. FMC lines 3L and 4L were BLANK! I then said; 'Forget it. SPEED INTERVENE 260' as that would keep us safe and technically comply with the speed limits below 10;000 ft. He did not immediately respond so I forcefully pointed to the MCP speed window. When the PM (Pilot Monitoring) complied we were at 260 KIAS and the FD immediately pitched-up to maintain that speed. The FO went heads-down again and started typing again trying to change the VNAV CLB page. He finally said after 10-15 seconds; 'it won't take it' and gave-up. Within a few more seconds we were at 7000 ft and the PM called-out '7000 for 8000' to which I replied; 'seven for eight' as confirmation and placed my right hand on the throttles; as a technique as I have always done; to remind myself that we were about to level-off. The FMA's at the time were: THR REF LNAV VNAVSPD and we were climbing at about 3500 FPM. Things had fully stabilized in the cockpit and I said; 'Let's try managed speed again and see if it doesn't give us 252'. He reached-up and closed the window and the speed changed to 322 KIAS; and the flight director commanded a pitch-down for the acceleration. The FO went heads-down again and started typing and I said; 'Speed intervene 260'...he did not reply and stayed heads-down. I then took my right hand off of the throttles reached up and opened the window and dialed the speed back to 252 KIAS. When I looked back at the HUD the FMA was still annunciating THR REF LNAV VNAV SPD and the FD command bar was commanding a pitch-up maneuver which I ignored! Scanning the altitude tape we were at 7900 Ft! I began to push forward on the yoke for the level-off disregarding the FD commands completely. The FMA's DID NOT change to: SPD LNAV VNAV PTH until we were at 8100 ft and the flight director DID NOT command a pitch-down until 2-3 seconds after that! I manually was pulling the thrust levers back and pushing forward on the yoke as much as I could without having the G-loading decrease much below 1-G. During the maneuver we climbed to 8300 ft before descending back to 8000 ft. The PM said; 'Watch your altitude' to which I replied;' I'm pushing as hard as I can without everyone doing the moonwalk'. ATC queried us about our level-off when we weredescending from 8100 ft to 8000 ft and told us to watch for traffic ahead and above us. The TCAS indicated the traffic ahead was still at least 5 miles out. We resumed the climb after receiving clearance to do so and remained in speed intervene mode until passing 10;000ft. When we closed the window at 10000 ft the commanded speed again advanced to 322 KIAS. I do not know what happened to the FMC VNAV CLB page LINE 3L 'SPD TRANS' entry of 250/10000 at 3000 AGL. But this SOP change may have created an unintended consequence. Also; when I was trained last summer on the 787 the instructors DEMANDED that I stay on the TAKEOFF REF page when I am flying the airplane so I can; 'see the V speeds' as opposed to being on the VNAV page; as EVERY OTHER FLEET AT THIS AIRLINE DOES so the PF can see the VNAV speeds at 2L; 3L and 4L while climbing. From now on I WILL be on the VNAV page when I start the takeoff roll which the SOP does allow! Also; the propensity of Pilots Monitoring; as they have been rigorously trained to do; to go heads-down when encountering auto-flight anomalies is a HUGE hazard to flight safety in the takeoff and landing phases of flight. In my humble opinion; we should have our heads up and primarily out of the cockpit below 10;000 ft unless we are in the clouds or ATC has given us a clearance that demands that the PM be heads down to enable the clearance. If I had to do it again; I obviously would NOT call for the speed window to be closed when about to level the airplane as it caused an unnecessary distraction in a time compressed situation when all we needed to be doing was leveling the airplane at 8000 ft: I take the responsibility for that poor decision - the altitude incident was of my own doing. Additionally; I would like to say to those who use the autopilot as a crutch; 'If only the autopilot had been engaged' - I HAVE NO DOUBT WHATSOEVER that if the autopilot had been engaged we not only would have busted the altitude by 300 ft; it would have been a MUCH GREATER bust and a huge speed bust as well given the late FMA's and the FD commands passing our cleared altitude. As we all know; auto-flight works well if it has the time to think about it but; does NOT do well in time compressed situations. And YES we debriefed the incident in detail using the FM as a reference not only on that flight but; the flight the next day also.
B787 Captain reported that the new procedure to manually enter Vref 30+80/3000 AGL on VNAV CLB LS page 4L (252 knots) caused the aircraft to attempt to accelerate to 322 knots at that altitude. While troubleshooting; the intended level off altitude was exceeded by 300 feet.