Automatic throttles disconnected resulting in autoplt changing modes and altitude excursion of 400'.

Attributes
ACN	90246
Time
Date	198807
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : mei
State Reference	MS
Altitude	msl bound lower : 33000 msl bound upper : 33400
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zme
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	cruise other
Route In Use	enroute airway : zme
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : commercial pilot : flight engineer
Experience	flight time last 90 days : 150 flight time total : 3000 flight time type : 150
ASRS Report	90246
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : commercial pilot : atp
Experience	flight time last 90 days : 80 flight time total : 7500 flight time type : 115
ASRS Report	90235
Events
Anomaly	altitude deviation : excursion from assigned altitude
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Enroute from sat to atl level at FL330. FMS navigation and speed engaged. Captain (PNF) doing engine log and first officer (PF) doing a route intercept on the FMS. Both pilots attention diverted away from navigation display panel. To copy the number for the engine log. The captain (PNF) disengaged the automatic throttles. The FMS (autoplt) then went into a mach airspeed mode which will maintain mach re: of altitude. Again, with our attention diverted we did not see this on the FMA panel. The altitude alert went off at a 300' deviation as advertised. The first officer (PF) immediately disengaged the autoplt and throttles and flew the aircraft back to FL330. The aircraft had climbed through FL334. No mention of the event from center. Autoplts need to be more 'user friendly.' these things need constant attention. 2-M crews don't have time to babysit the mode panel to see what the autoplt wants to do today. This is a frustrating problem. This is my third altitude deviation report in 1 month.

Original NASA ASRS Text

Title: AUTO THROTTLES DISCONNECTED RESULTING IN AUTOPLT CHANGING MODES AND ALT EXCURSION OF 400'.

Narrative: ENROUTE FROM SAT TO ATL LEVEL AT FL330. FMS NAV AND SPEED ENGAGED. CAPT (PNF) DOING ENG LOG AND F/O (PF) DOING A ROUTE INTERCEPT ON THE FMS. BOTH PLTS ATTN DIVERTED AWAY FROM NAV DISPLAY PANEL. TO COPY THE NUMBER FOR THE ENG LOG. THE CAPT (PNF) DISENGAGED THE AUTO THROTTLES. THE FMS (AUTOPLT) THEN WENT INTO A MACH AIRSPD MODE WHICH WILL MAINTAIN MACH RE: OF ALT. AGAIN, WITH OUR ATTN DIVERTED WE DID NOT SEE THIS ON THE FMA PANEL. THE ALT ALERT WENT OFF AT A 300' DEVIATION AS ADVERTISED. THE F/O (PF) IMMEDIATELY DISENGAGED THE AUTOPLT AND THROTTLES AND FLEW THE ACFT BACK TO FL330. THE ACFT HAD CLBED THROUGH FL334. NO MENTION OF THE EVENT FROM CENTER. AUTOPLTS NEED TO BE MORE 'USER FRIENDLY.' THESE THINGS NEED CONSTANT ATTN. 2-M CREWS DON'T HAVE TIME TO BABYSIT THE MODE PANEL TO SEE WHAT THE AUTOPLT WANTS TO DO TODAY. THIS IS A FRUSTRATING PROB. THIS IS MY THIRD ALT DEV RPT IN 1 MONTH.

Data retrieved from NASA's ASRS site as of August 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.