Flight Crew Last 90 Days 154
Human-Machine Interface; Communication Breakdown; Confusion
Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance
Flight Crew FLC Overrode Automation; Flight Crew Overcame Equipment Problem
Human Factors
On left base visual to 25L with the autopilot on; looking over left shoulder to spot traffic and the runway; the Captain selected the approach mode instead of the LOC button. This caused the airplane to climb 500 feet above altitude. As soon as the engines started to spool; I informed the Captain that we were about to start climbing out of our assigned altitude. He was not sure what to do; as he started pushing buttons to get the airplane to level off. After a few moments of letting him try to solve the solution; I asked him to turn off the autopilot; which he eventually did; and returned the aircraft to its intended flight path. He completed the visual approach with a slight overshoot. I should have intervened right away; instead of waiting for him to figure out the automation. I'll be less respectful of positional authority; and more respectful of the possible consequences.
We were at 5;500 feet on a base leg flying a visual approach. I intended to arm the VOR/LOC mode on the MCP. However; I accidentally armed the APP mode. The autopilot then captured a glideslope signal. The aircraft quickly began to climb. This resulted in a 500 foot deviation error. I immediately disconnected the autopilot and corrected the flight path.Correctly verbalizing and verifying automation changes would prevent this error.
Inadvertently selecting APP mode vice VOR/LOC to intercept the localizer while on autopilot resulted in a glide slope capture and a climb out of their cleared altitude for a B737NG flight crew.