Altitude deviation.

Attributes
ACN	296528
Time
Date	199502
Day	Wed
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : lga airport : jfk
State Reference	NY
Altitude	msl bound lower : 18300 msl bound upper : 19000
Environment
Flight Conditions	Mixed
Light	Night
Aircraft 1
Controlling Facilities	artcc : zny
Operator	common carrier : air carrier
Make Model Name	L-1011 Tri-Star All Series
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	cruise other descent other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : flight engineer pilot : cfi pilot : atp
Experience	flight time last 90 days : 25 flight time total : 5000 flight time type : 25
ASRS Report	296528
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : atp
Experience	flight time last 90 days : 150 flight time total : 20000 flight time type : 2800
ASRS Report	296530
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance flight crew : returned to intended course or assigned course flight crew : became reoriented
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

Approaching lga VOR from the west at about 30 DME, aircraft had just leveled at FL190 (from descent) when autoplt tripped off (from cmd to cws) and aircraft descended to about 18500 ft before captain recovered by hand flying L1011 back to FL190. On the L1011, the autoplt gives no aural or visual warnings when it trips from cmd to cws. Flight director shares autoplt annunciator, thus the flight directors continue to 'command' heading altitude hold, etc, even though autoplt is no longer in command (but tripped to cws). Additionally, the autoplt has no lighting on autoplt paddle switches. Phosphorescent paint has been completely worn off in over 20 yrs of use supplemental information from acn 296530: cockpit crew busy reviewing approach plate for jfk. There was no warning of autoplt disengagement.

Original NASA ASRS Text

Title: ALTDEV.

Narrative: APCHING LGA VOR FROM THE W AT ABOUT 30 DME, ACFT HAD JUST LEVELED AT FL190 (FROM DSCNT) WHEN AUTOPLT TRIPPED OFF (FROM CMD TO CWS) AND ACFT DSNDED TO ABOUT 18500 FT BEFORE CAPT RECOVERED BY HAND FLYING L1011 BACK TO FL190. ON THE L1011, THE AUTOPLT GIVES NO AURAL OR VISUAL WARNINGS WHEN IT TRIPS FROM CMD TO CWS. FLT DIRECTOR SHARES AUTOPLT ANNUNCIATOR, THUS THE FLT DIRECTORS CONTINUE TO 'COMMAND' HDG ALT HOLD, ETC, EVEN THOUGH AUTOPLT IS NO LONGER IN COMMAND (BUT TRIPPED TO CWS). ADDITIONALLY, THE AUTOPLT HAS NO LIGHTING ON AUTOPLT PADDLE SWITCHES. PHOSPHORESCENT PAINT HAS BEEN COMPLETELY WORN OFF IN OVER 20 YRS OF USE SUPPLEMENTAL INFO FROM ACN 296530: COCKPIT CREW BUSY REVIEWING APCH PLATE FOR JFK. THERE WAS NO WARNING OF AUTOPLT DISENGAGEMENT.

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.