<< >> NASA ASRS Report 332140, March 1996

Altitude deviation. PNF, captain, was cleaning fluid spill on autoplt control head and when re-engaging the autoplt forgot to engage altitude hold. Aircraft started gradual climb and not noticed by flight crew until altitude alert warning sounded.

Attributes
ACN	332140
Time
Date	199603
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : ama
State Reference	TX
Altitude	msl bound lower : 31000 msl bound upper : 31500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zab
Operator	common carrier : air carrier
Make Model Name	B727-200
Operating Under FAR Part	Part 121
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : second officer
Qualification	pilot : flight engineer pilot : instrument pilot : atp pilot : commercial
Experience	flight time last 90 days : 220 flight time total : 12000 flight time type : 4000
ASRS Report	332140
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : flight engineer pilot : commercial pilot : cfi pilot : atp
Experience	flight time last 90 days : 100 flight time total : 17500 flight time type : 2000
ASRS Report	331786
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	other controllera other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I was the so on flight from atl to phx. It was the copilot's leg. In the vicinity of ama VOR the captain noted a liquid spill on the autoplt control head. The captain disconnected the autoplt to clean below the autoplt engage/disengage switches. This cleaning was momentary and captain re-engaged autoplt. He did not insure that altitude hold was re-engaged. Aircraft began an uncommanded slow climb which was unnoticed. Deviation was noted by all crew members when altitude alert sounded at +500 ft (FL315). Autoplt was immediately disengaged and aircraft was smoothly returned to altitude (FL310), to prevent any passenger discomfort. Just after corrective action was initiated to return to assigned altitude, ATC noted deviation and requested our altitude. Maximum deviation was 500 ft.

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Original NASA ASRS Text

Title: ALTDEV. PNF, CAPT, WAS CLEANING FLUID SPILL ON AUTOPLT CTL HEAD AND WHEN RE-ENGAGING THE AUTOPLT FORGOT TO ENGAGE ALT HOLD. ACFT STARTED GRADUAL CLB AND NOT NOTICED BY FLC UNTIL ALT ALERT WARNING SOUNDED.

Narrative: I WAS THE SO ON FLT FROM ATL TO PHX. IT WAS THE COPLT'S LEG. IN THE VICINITY OF AMA VOR THE CAPT NOTED A LIQUID SPILL ON THE AUTOPLT CTL HEAD. THE CAPT DISCONNECTED THE AUTOPLT TO CLEAN BELOW THE AUTOPLT ENGAGE/DISENGAGE SWITCHES. THIS CLEANING WAS MOMENTARY AND CAPT RE-ENGAGED AUTOPLT. HE DID NOT INSURE THAT ALT HOLD WAS RE-ENGAGED. ACFT BEGAN AN UNCOMMANDED SLOW CLB WHICH WAS UNNOTICED. DEV WAS NOTED BY ALL CREW MEMBERS WHEN ALT ALERT SOUNDED AT +500 FT (FL315). AUTOPLT WAS IMMEDIATELY DISENGAGED AND ACFT WAS SMOOTHLY RETURNED TO ALT (FL310), TO PREVENT ANY PAX DISCOMFORT. JUST AFTER CORRECTIVE ACTION WAS INITIATED TO RETURN TO ASSIGNED ALT, ATC NOTED DEV AND REQUESTED OUR ALT. MAX DEV WAS 500 FT.

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.