An FMS and related autoflt failure distracted a flight crew from meeting a crossing restr.

Attributes
ACN	301471
Time
Date	199504
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : bwz airport : ewr
State Reference	NJ
Altitude	msl bound lower : 7000 msl bound upper : 7500
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	arrival other arrival star : star enroute airway : zny
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 240 flight time total : 18500 flight time type : 672
ASRS Report	301471
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : flight engineer pilot : cfi
Experience	flight time last 90 days : 100 flight time total : 9500 flight time type : 150
ASRS Report	301830
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : crossing restriction not met non adherence : clearance other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : overcame equipment problem other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

On descent into ewr airport, on the williamsport 1 arrival, navigating on FMS-RNAV route, the FMS overloaded and dumped the route off the control display unit. The copilot was flying at the time and captain was operating the radios. The autoplt disconnected with loss of route. The copilot flew the aircraft manually and the captain reloaded the data into the FMS to activate the route again. The clearance was to cross sweet intersection at 7000 ft. In the confusion the copilot crossed the intersection at about 7500 ft. There was no conflict with traffic at the time. Center turned the aircraft to a heading of 080 degrees for vectors for approach to runway C22L at newark. Supplemental information from acn 301830: both FMC's dumped all data, and the autothrottles and autoplt disconnected at approximately 10000 ft MSL. I hand flew the aircraft while the captain continued to man radios, perform checklists, and reload the computers. Upon attempting to reengage the autoflt system, the autothrottles and autoplt did not respond properly, so we elected to discontinue use of all autoflt functions. We also began to encounter intermittent light to occasional moderate turbulence.

Original NASA ASRS Text

Title: AN FMS AND RELATED AUTOFLT FAILURE DISTRACTED A FLC FROM MEETING A XING RESTR.

Narrative: ON DSCNT INTO EWR ARPT, ON THE WILLIAMSPORT 1 ARR, NAVING ON FMS-RNAV RTE, THE FMS OVERLOADED AND DUMPED THE RTE OFF THE CTL DISPLAY UNIT. THE COPLT WAS FLYING AT THE TIME AND CAPT WAS OPERATING THE RADIOS. THE AUTOPLT DISCONNECTED WITH LOSS OF RTE. THE COPLT FLEW THE ACFT MANUALLY AND THE CAPT RELOADED THE DATA INTO THE FMS TO ACTIVATE THE RTE AGAIN. THE CLRNC WAS TO CROSS SWEET INTXN AT 7000 FT. IN THE CONFUSION THE COPLT CROSSED THE INTXN AT ABOUT 7500 FT. THERE WAS NO CONFLICT WITH TFC AT THE TIME. CTR TURNED THE ACFT TO A HDG OF 080 DEGS FOR VECTORS FOR APCH TO RWY C22L AT NEWARK. SUPPLEMENTAL INFO FROM ACN 301830: BOTH FMC'S DUMPED ALL DATA, AND THE AUTOTHROTTLES AND AUTOPLT DISCONNECTED AT APPROX 10000 FT MSL. I HAND FLEW THE ACFT WHILE THE CAPT CONTINUED TO MAN RADIOS, PERFORM CHKLISTS, AND RELOAD THE COMPUTERS. UPON ATTEMPTING TO REENGAGE THE AUTOFLT SYS, THE AUTOTHROTTLES AND AUTOPLT DID NOT RESPOND PROPERLY, SO WE ELECTED TO DISCONTINUE USE OF ALL AUTOFLT FUNCTIONS. WE ALSO BEGAN TO ENCOUNTER INTERMITTENT LIGHT TO OCCASIONAL MODERATE TURB.

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.