An air carrier B727-200 flight crew climbs above its assigned altitude when the wrong autoplt pitch ...

Attributes
ACN	363373
Time
Date	199703
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : bvl
State Reference	UT
Altitude	msl bound lower : 33000 msl bound upper : 33450
Environment
Flight Conditions	VMC
Light	Dusk
Aircraft 1
Controlling Facilities	artcc : zlc tracon : san
Operator	common carrier : air carrier
Make Model Name	B727-200
Operating Under FAR Part	Part 121
Flight Phase	cruise other
Route In Use	enroute airway : zlc
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Experience	flight time last 90 days : 250 flight time total : 6000 flight time type : 1500
ASRS Report	363373
Person 2
Affiliation	company : air carrier
Function	flight crew : second officer
Qualification	pilot : instrument pilot : flight engineer pilot : commercial pilot : atp
Experience	flight time last 90 days : 100 flight time total : 5000 flight time type : 2000
ASRS Report	363471
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : published procedure non adherence : clearance non adherence : far
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We were level at 33000 ft with the block V autoplt engaged on altitude hold only. The B727 was climbing through 33400 ft when I noticed the climb. I disengaged the autoplt and returned to 33000 ft MSL. We then noticed the pitch control knob in the mach hold position, which was labled 'inoperative.' I placed the knob back into the 'vertical speed' position and engaged the autoplt in altitude hold. The remainder of the flight was normal. Supplemental information from acn 363471: upon further investigation, we found the pitch selector (this is a mode 5 autoplt) in 'mach hold' -- a position which is supposed to be inoperative. Apparently it still worked. Once the pitch selector was returned to vertical speed, everything was normal. How did the pitch selector get to 'mach hold?' a few mins prior, a flight attendant had come forward to view the hale-bopp comet. She had leaned forward to view it out of the cockpit window and, I'm guessing, may have unintentially moved the pitch selector.

Original NASA ASRS Text

Title: AN ACR B727-200 FLC CLBS ABOVE ITS ASSIGNED ALT WHEN THE WRONG AUTOPLT PITCH MODE WAS SELECTED.

Narrative: WE WERE LEVEL AT 33000 FT WITH THE BLOCK V AUTOPLT ENGAGED ON ALT HOLD ONLY. THE B727 WAS CLBING THROUGH 33400 FT WHEN I NOTICED THE CLB. I DISENGAGED THE AUTOPLT AND RETURNED TO 33000 FT MSL. WE THEN NOTICED THE PITCH CTL KNOB IN THE MACH HOLD POS, WHICH WAS LABLED 'INOP.' I PLACED THE KNOB BACK INTO THE 'VERT SPD' POS AND ENGAGED THE AUTOPLT IN ALT HOLD. THE REMAINDER OF THE FLT WAS NORMAL. SUPPLEMENTAL INFO FROM ACN 363471: UPON FURTHER INVESTIGATION, WE FOUND THE PITCH SELECTOR (THIS IS A MODE 5 AUTOPLT) IN 'MACH HOLD' -- A POS WHICH IS SUPPOSED TO BE INOP. APPARENTLY IT STILL WORKED. ONCE THE PITCH SELECTOR WAS RETURNED TO VERT SPD, EVERYTHING WAS NORMAL. HOW DID THE PITCH SELECTOR GET TO 'MACH HOLD?' A FEW MINS PRIOR, A FLT ATTENDANT HAD COME FORWARD TO VIEW THE HALE-BOPP COMET. SHE HAD LEANED FORWARD TO VIEW IT OUT OF THE COCKPIT WINDOW AND, I'M GUESSING, MAY HAVE UNINTENTIALLY MOVED THE PITCH SELECTOR.

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.

An air carrier B727-200 flight crew climbs above its assigned altitude when the wrong autoplt pitch mode was selected.