Flight Crew Air Transport Pilot (ATP)
Communication Breakdown; Distraction; Human-Machine Interface; Workload
Aircraft Equipment Problem Less Severe; Deviation - Altitude Crossing Restriction Not Met; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Returned To Clearance; Flight Crew Became Reoriented; Flight Crew Took Evasive Action
Aircraft; Human Factors
We were radar vectored; then cleared direct GRAMM RIIVR 2 arrival to 25L ILS and instructed to hold 300 KTS. We set up VNAV Path set 1;900 FT in ALT window of Mode Control Panel (MCP). Approaching LUVYN ATC ordered a slow down to 250 KTS. The First Officer who was Pilot Flying deployed speedbrakes and did not think we were slowing fast enough and shallowing our descent fast enough so he selected vertical speed on mode control and slowed sink to slow to 250 KTS. At approximately the same time we had a TCAS FAIL MSG on the ND and XPONDER FAIL LIGHT on the transponder unit. These warning lights help distract me the Captain and Pilot Not Flying at a critical time. We still had 1;900 FT set in the ALT window on the Mode Control Panel from the VNAV path descent for FAF LIMMA. We should have set 10;000 FT in the ALT window for KRAIN once we left VNAV path but failed to do it in time resulting in us going below the 10;000 FT crossing restriction at KRAIN. We corrected back to the path and continued the approach and landing without further problem.
We were being vectored to the arrival and given direct GRAMM with a directed speed of 300 KTS. We were cleared the arrival and placed 1;900 FT in the altitude window. We approached LUVYN and requested a speed reduction to 250 KTS. As we were slowing and descending to the 10;000 FT restriction; the aircraft was in VNAV mode. At 11;000 FT our descent rate was 2;300 ft/min and I felt the aircraft was going to descend through the restricted altitude; I selected Vertical Speed to slow the descent rate; taking us out of VNAV. The restricted altitude was not subsequently put into the MCP altitude window. As I verified the speedbrakes were stowed and VNAV re-selected; I noticed our altitude had descended below 10;000 FT; as was required. I leveled off for the next fix TAROC. We completed the remainder of the approach without any other issues. At this approximate time; we received a TCAS and Transponder malfunction warning; further complicating our work load.
A B737-800 crew flying the RIIVR 2 arrival set 1;900 FT in the MCP ALT for the Runway 25L FAF; then selected VS to begin slowing to 250 KTS at 10;000 FT but became distracted and forgot to re-select VNAV. They descended to 8;500 FT before KRAIN.