B737-800
Flight Crew Air Transport Pilot (ATP)
Communication Breakdown; Human-Machine Interface
ATC Issue All Types; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Became Reoriented
Human Factors; Procedure
Upon tracking the JOVEM Arrival we received multiple airspeed and altitude changes including cleared to FL240; FL220 then via the JOVEM Arrival to 8000 feet; then back to 11000 feet; 270 knots; 250 knots; 280 knots then back to 250 knots. Theses rapid fire changes even persisted throughout final with two additional airspeed changes up to the final fix; (eight airspeed changes and five altitude changes). We were in level change while making one of the changes to the FMC when we noticed we were below 12000 prior to JOVEM. We promptly returned to 12000 and proceeded on the arrival uneventful.Please reduce the number of airspeed and altitude changes during descents and approaches. Our changes today occurred up to; and including; the final approach fix even though we were cleared a visual.
Arriving expecting the JOVEM Arrival; ATC gave us a different point with crossing restriction and three speed changes before the first crossing restriction point on the arrival. The changes came so quickly and in close that we could not program the FMC fast enough; forcing us to use level change; with the speedbrakes fully extended. ATC then gave us another speed change and 'via the JOVEM Arrival.' We put 8000 in the altitude window as previously briefed; but we were still in level change. We went below 12000 prior to JOVEM. We stopped the descent; climbed back to 12000 in Vertical Speed; and re-engaged VNAV/LNAV with speed intervene. We continued to be taken off the vertical portion of the arrival; and continued to receive speed changes all the way to the marker. Eight speed changes; and 5 altitude changes until being cleared for the visual approach to 35C. ATC cannot give out that many speed and altitude changes on an arrival - it was beyond the capability of the FMC. For myself; I should have reset my thought process from trying to get to VNAV; to all manual much further out.
During arrival procedure; B-737 crew overshot published minimum altitude. Crew had received numerous altitude and airspeed changes from ATC and neglected to engage VNAV.