A B757 flight crew inadvertently selected wrong button on the mode control selector, resulting in an...

Attributes
ACN	520810
Time
Date	200108
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	navaid : pdz.vortac
State Reference	CA
Altitude	msl bound lower : 11000 msl bound upper : 12000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Flight Phase	descent : approach
Route In Use	arrival star : n/s
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer observation : company check pilot
Qualification	pilot : atp
Experience	flight time last 90 days : 100 flight time total : 12500 flight time type : 2000
ASRS Report	520810
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : overshoot non adherence : clearance
Resolutory Action	flight crew : took precautionary avoidance action flight crew : overcame equipment problem flight crew : overrode automation
Supplementary
Problem Areas	ATC Human Performance Aircraft
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

This trip was a line operating experience (loe) for a new captain (left seat, PF) being administered by another captain acting as first officer (right seat, PNF). The paradise arrival to lax was being flown with the FMS as a demonstration with both VNAV and LNAV engaged to 250 KTS. All vertical and lateral controls were being commanded by the FMS and autoflt system. When a speed reduction was directed by socal approach the speed select button was pushed (in error) instead of selecting speed intervention on the autoflt control panel. The line check pilot did not notice the error until a xchk at the pdz VOR -- minimum altitude is 12000 ft, aircraft was approaching 11000 ft MSL. We immediately stopped the descent and then continued without incident. We were task saturated -- go down, slow down, radio calls, checklists, and trying to explain the approach and how to best handle the slow down/go down maneuver. I saw him hit the button (right next to the correct button) saw the speed window open for the slow down, but did not notice we came out of VNAV and were in vertical speed. We flew right through the altitude.

Original NASA ASRS Text

Title: A B757 FLT CREW INADVERTENTLY SELECTED WRONG BUTTON ON THE MODE CTL SELECTOR, RESULTING IN AN OVERSHOOT OF THEIR ASSIGNED ALT.

Narrative: THIS TRIP WAS A LINE OPERATING EXPERIENCE (LOE) FOR A NEW CAPT (L SEAT, PF) BEING ADMINISTERED BY ANOTHER CAPT ACTING AS FO (R SEAT, PNF). THE PARADISE ARR TO LAX WAS BEING FLOWN WITH THE FMS AS A DEMONSTRATION WITH BOTH VNAV AND LNAV ENGAGED TO 250 KTS. ALL VERT AND LATERAL CTLS WERE BEING COMMANDED BY THE FMS AND AUTOFLT SYS. WHEN A SPD REDUCTION WAS DIRECTED BY SOCAL APCH THE SPD SELECT BUTTON WAS PUSHED (IN ERROR) INSTEAD OF SELECTING SPD INTERVENTION ON THE AUTOFLT CTL PANEL. THE LINE CHK PLT DID NOT NOTICE THE ERROR UNTIL A XCHK AT THE PDZ VOR -- MINIMUM ALT IS 12000 FT, ACFT WAS APCHING 11000 FT MSL. WE IMMEDIATELY STOPPED THE DSCNT AND THEN CONTINUED WITHOUT INCIDENT. WE WERE TASK SATURATED -- GO DOWN, SLOW DOWN, RADIO CALLS, CHKLISTS, AND TRYING TO EXPLAIN THE APCH AND HOW TO BEST HANDLE THE SLOW DOWN/GO DOWN MANEUVER. I SAW HIM HIT THE BUTTON (RIGHT NEXT TO THE CORRECT BUTTON) SAW THE SPD WINDOW OPEN FOR THE SLOW DOWN, BUT DID NOT NOTICE WE CAME OUT OF VNAV AND WERE IN VERT SPD. WE FLEW RIGHT THROUGH THE ALT.

Data retrieved from NASA's ASRS site as of July 2007 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.

A B757 flight crew inadvertently selected wrong button on the mode control selector, resulting in an overshoot of their assigned altitude.