B737 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 124; Flight Crew Type 11000
Deviation - Altitude Crossing Restriction Not Met; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Human Factors; Procedure
Our PDC was to climb via the SNSET1 RNAV Departure CIKAN transition.  The First Officer (FO) did a very thorough Clearance and Departure briefing.  He was to be the Pilot Flying (PF) for this leg.  He said we would set 7;000 feet in the MCP to comply with the 5;000-7;000 feet restriction at ARILE until we had the aircraft in VNAV.  We had LNAV armed prior to takeoff and he got the airplane on autopilot and autothrottle shortly after the aircraft was cleaned up and selected VNAV.  After coordination with him; I set 10;000 feet in the MCP which is the maintain altitude for the departure.  Everything went as briefed to include checking in with Departure.  About 2.5 miles prior to ARILE and around 6;500 feet with a rapid climb; Departure Control gave us a clearance to 'climb via the SID except maintain 17;000.' I saw the FO's left hand start to move up toward the MCP.  As I was saying; 'don't push that;' he had pushed the ALT INTV button.  With our rapid climb rate; I took control of the aircraft; and disconnected the autopilot and autothrottle to minimize overshoot of the 7;000-foot restriction.  We had a significant overshoot and got up to about 7;400 feet before the climb stopped. Once things settled down; we covered what had gone wrong; basically a breakdown in CRM.  The FO thought the Departure Control instructions meant to climb unrestricted to 17;000 feet and realized he had deleted the ARILE restriction in haste.  He also said he was having difficulty grasping inflight changes to 'Climb Via' clearances.  While this was a breakdown in Crew coordination; the additive condition of a clearance change so near an action point contributed to our error. We debriefed the importance of proper verification before changing any vertical or navigation programming.  Today we will review the 'Climb Via' clearance changes in some depth.  They can be confusing and are often less clear than 'Descend Via' clearances.  Often the pilot monitoring can be the tie breaker.
I was Pilot Flying (PF); Captain was Pilot Monitoring (PM). In the Departure brief; I discussed altitude restriction of 5;000-7;000 feet crossing ARILE waypoint while climbing to 10;000 feet in accordance with the 'climb via SID' clearance. MCP altitude was set to 7;000 feet for departure in order to ensure compliance. I briefed plan to reset MCP to 10;000 feet after ensuring VNAV was active mode and that the 7;000 feet restriction at ARILE would be met. Takeoff and initial climb proceeded normally. After the autopilot was engaged; and the aircraft was verified in VNAV; 10;000 feet was set in the MCP altitude window in accordance with the SID climb clearance. As the aircraft began to level at 7;000 feet; approximately three NM prior to ARILE waypoint; ATC (Regional Departure); issued a further clearance to 'climb via the SNSET 1 except maintain 17;000 feet.' I mistakenly interpreted the ATC instructions as continue climb to 17;000 feet. I inserted 17;000 feet in the MCP window; and without pausing to think or review the exact instructions; or verify the instructions with the PM; I pushed the Altitude Intervention button on the MCP. The aircraft immediately began to climb out of 7;000 feet; approximately two to two and one-half NM prior to ARILE. The Captain; as pilot monitoring (PM); immediately recognized the error. He called for control of the aircraft and disengaged the autopilot and autothrottles and leveled; and then descended back to 7;000 feet. We reached a maximum altitude of 7;500 feet. As the Captain took control of the aircraft; I realized the error I had made; and my misunderstanding/misinterpretation of the climb instructions from ATC. It was a mistake that could have easily been avoided by simply dialing in the new clearance altitude of 17;000 feet and not pressing Altitude Intervention. Instead of rushing; I could have used better Crew Coordination and taken a moment to verify with the Captain that we both agreed what the ATC climb instructions were; and that we agreed with regards to the correct action to comply with those instructions from ATC.ATC; did not express concern or query us about our brief altitude deviation. After leveling back at 7;000 feet and past ARILE waypoint; the Captain verified our climb clearance with ATC and we proceeded to climb via the SID to 17;000 feet. Do not rush. Use better Crew Coordination and verify an action with fellow Crew Member; PM; before executing the action. Pay better attention to departure climb instructions. Do not get complacent or assume that a further climb instruction is an unrestricted climb just because that is what ATC usually gives us or that is what they gave me last time.
B737 flight crew on the SNSET 1 RNAV departure; with the First Officer flying; describes missing a crossing restriction after being assigned a new top altitude by ATC and pushing the altitude intervention button on the MCP instead of just setting the new altitude. The Captain takes control to mitigate the overshoot.