B737-400 started descent late for crossing restr when near ZNY.

Attributes
ACN	422911
Time
Date	199812
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : jst
State Reference	PA
Altitude	msl bound lower : 25000 msl bound upper : 33000
Environment
Flight Conditions	VMC
Light	Dusk
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737-400
Flight Phase	cruise other descent other landing other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : cfi
Experience	flight time last 90 days : 250 flight time total : 17500 flight time type : 5000
ASRS Report	422911
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial
Events
Anomaly	non adherence : clearance other anomaly other
Independent Detector	other flight crewa
Resolutory Action	other
Consequence	Other
Supplementary
Air Traffic Incident	Pilot Deviation

Narrative:

Cleared from cruise at 33000 ft to cross cofax at 25000 ft. We confirmed the altitude in the cockpit. A flight attendant entered the cockpit and I turned away to deal with that. The first officer's brain briefly vapor locked and entered the FL250 restr on the cruise page instead of as a descent restr. This drove the autoplt to a 1000 FPM descent, instead of making the restr. I got back in the loop at FL310, 19 mi from the fix with 140 KT tailwind. We advised center of our problem. They cleared us to maintain FL250 -- eliminating the restr. 1) both pilots needed in loop -- we can't eliminate flight attendant presence in the cockpit but maybe it should be restr to cruise. 2) FMS can't indicate upcoming non compliance with crossing restrs when there is an altitude entered on cruise page lower than aircraft. Maybe we should restr use of cruise descent.

Original NASA ASRS Text

Title: B737-400 STARTED DSCNT LATE FOR XING RESTR WHEN NEAR ZNY.

Narrative: CLRED FROM CRUISE AT 33000 FT TO CROSS COFAX AT 25000 FT. WE CONFIRMED THE ALT IN THE COCKPIT. A FLT ATTENDANT ENTERED THE COCKPIT AND I TURNED AWAY TO DEAL WITH THAT. THE FO'S BRAIN BRIEFLY VAPOR LOCKED AND ENTERED THE FL250 RESTR ON THE CRUISE PAGE INSTEAD OF AS A DSCNT RESTR. THIS DROVE THE AUTOPLT TO A 1000 FPM DSCNT, INSTEAD OF MAKING THE RESTR. I GOT BACK IN THE LOOP AT FL310, 19 MI FROM THE FIX WITH 140 KT TAILWIND. WE ADVISED CTR OF OUR PROB. THEY CLRED US TO MAINTAIN FL250 -- ELIMINATING THE RESTR. 1) BOTH PLTS NEEDED IN LOOP -- WE CAN'T ELIMINATE FLT ATTENDANT PRESENCE IN THE COCKPIT BUT MAYBE IT SHOULD BE RESTR TO CRUISE. 2) FMS CAN'T INDICATE UPCOMING NON COMPLIANCE WITH XING RESTRS WHEN THERE IS AN ALT ENTERED ON CRUISE PAGE LOWER THAN ACFT. MAYBE WE SHOULD RESTR USE OF CRUISE DSCNT.

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.