B737 captain reported descending on the iah DRLLR5 arrival for runway 26R then assigned runway 27 an...

Attributes
ACN	1415751
Time
Date	201701
Local Time Of Day	0601-1200
Place
Locale Reference	IAH.Airport
State Reference	TX
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Route In Use	STAR DRLLR5
Flight Plan	IFR
Component
Aircraft Component	FMS/FMC
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 120 Flight Crew Type 755
Events
Anomaly	ATC Issue All Types Deviation - Altitude Crossing Restriction Not Met Deviation - Altitude Undershoot Deviation - Procedural Published Material / Policy

Narrative:

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 runway 26R and we were changed to the transition for runway 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.

Original NASA ASRS Text

Title: 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.

Narrative: 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.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

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.