B737 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 120; Flight Crew Type 755
Communication Breakdown; Situational Awareness
ATC Issue All Types; Deviation - Altitude Crossing Restriction Not Met; Deviation - Altitude Undershoot; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Aircraft; Human Factors; Procedure
While flying the DRLLR 5 arrival into IAH we crossed the BYSUN intersection at approximately 6500 feet. We should have crossed the intersection at the published altitude of 6000 feet. This happened for a couple of reasons. First was the distraction of the VNAV system not completely operating correctly. Every time speed intervene was selected; to comply with speed changes ATC gave us on the arrival; the autopilot flight director system would drop out of VNAV into CWS pitch mode. This was written up on arrival into IAH. Also; we were originally expecting to fly the transition for RWY 26R and we were changed to the transition for RWY 27 while descending on the DRLLR 5 arrival. This caused us to be high on the profile and miss the crossing altitude at BYSUN by 500 feet high. While realizing that we were going to be high on crossing the fix; I tried to contact ATC to tell them we were going to be high at BYSUN; but the frequency was too congested.
B737 Captain reported descending on the IAH DRLLR5 Arrival for Runway 26R then assigned Runway 27 and multiple speed adjustments. This resulted in crossing BYSUN 500 feet high.