Air carrier flight crew reported their aircraft descended below an RNAV arrival crossing restriction...

Narrative:

We were descending on the BLUZZ1 rnav arrival. We had been cleared to descend via and had set 3000 in the attitude window. We were in LNAV and VNAV. We had just reviewed a new ATIS that indicated runway 9 and the 36s were in use. Previously it had been 27 and the 36s. We had loaded 27 thinking it was a possibility. We received a drag required message. Our position was passing spker at about 14;500. Our speed was about 10 knots fast. Speed brake was extended to slow the aircraft. Understanding that we were where we needed to be; I began to load 36R in the FMS. While doing this the aircraft continued to descend instead of lose airspeed. As a result we got down to 13200 at the bluzz intersection before returning to 14000 at ltown. I can only think that changing the approach while near an altitude restriction had resulted in a negative outcome. We corrected back to the path as soon as we realized the deviation. On the human error side I believe I chose a poor time to change the approach in the FMS. I should have done a better job monitoring the correction to the proper speed. I made the mistake of thinking the frag required message would be resolved by the speed brake without any altitude deviation. The system issue is that it appears that changing the approach may have affected the ability of the aircraft to maintain the path.

Original NASA ASRS Text

Title: Air carrier flight crew reported their aircraft descended below an RNAV Arrival crossing restriction when a runway change was entered in the FMC.

Narrative: We were descending on the BLUZZ1 Rnav arrival. We had been cleared to Descend Via and had set 3000 in the attitude window. We were in LNAV and VNAV. We had just reviewed a new ATIS that indicated Runway 9 and the 36s were in use. Previously it had been 27 and the 36s. We had loaded 27 thinking it was a possibility. We received a drag required message. Our position was passing SPKER at about 14;500. Our speed was about 10 knots fast. Speed brake was extended to slow the aircraft. Understanding that we were where we needed to be; I began to load 36R in the FMS. While doing this the aircraft continued to descend instead of lose airspeed. As a result we got down to 13200 at the BLUZZ intersection before returning to 14000 at LTOWN. I can only think that changing the approach while near an altitude restriction had resulted in a negative outcome. We corrected back to the path as soon as we realized the deviation. On the human error side I believe I chose a poor time to change the approach in the FMS. I should have done a better job monitoring the correction to the proper speed. I made the mistake of thinking the frag required message would be resolved by the speed brake without any altitude deviation. The system issue is that it appears that changing the approach may have affected the ability of the aircraft to maintain the path.

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.

Attributes
ACN	1482868
Time
Date	201709
Local Time Of Day	1801-2400
Place
Locale Reference	MEM.Airport
State Reference	TN
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	Large Transport Low Wing 2 Turbojet Eng
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	STAR BLUZZ1
Flight Plan	IFR
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	Pilot Flying First Officer
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Deviation - Altitude Overshoot Deviation - Procedural Clearance

Air carrier flight crew reported their aircraft descended below an RNAV arrival crossing restriction when a runway change was entered in the FMC.