Flight crew failed to meet altitude crossing restr. Altitude deviation altitude undershot.

Attributes
ACN	319531
Time
Date	199510
Day	Tue
Local Time Of Day	0001 To 0600
Place
Locale Reference	atc facility : fjc
State Reference	PA
Altitude	msl bound lower : 11000 msl bound upper : 18000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zny tower : san
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	enroute 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 : 180 flight time total : 13000 flight time type : 3500
ASRS Report	319531
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : crossing restriction not met altitude deviation : undershoot non adherence : clearance non adherence other
Independent Detector	other controllera
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Clearance was received from center to cross allentown VOR at 11000 ft. Captain initiated descent from FL350. After receiving ATIS, a different runway was selected from FMC. Due to a software glitch on this aircraft, selecting a new runway after programming a crossing restr into the VNAV, will sometimes drop the crossing restr. This is a major trap with this aircraft and I have seen this occur many times. Although we both should have caught the event, several other factors contributed. Several flight attendants were present in the cockpit engaged in personal (non-work related) conversation between themselves and the flight deck crew. We should have asked them to leave at the top of descent when the workload increased. It had been a long day and both myself and the captain were tired. (Long duty day, west coast to east coast with a stop, and a several-hour-break in major hub.) I feel if I had used better CRM skills, I could have easily asked the flight attendants to leave because we were getting busy.

Original NASA ASRS Text

Title: FLC FAILED TO MEET ALT XING RESTR. ALTDEV ALT UNDERSHOT.

Narrative: CLRNC WAS RECEIVED FROM CTR TO CROSS ALLENTOWN VOR AT 11000 FT. CAPT INITIATED DSCNT FROM FL350. AFTER RECEIVING ATIS, A DIFFERENT RWY WAS SELECTED FROM FMC. DUE TO A SOFTWARE GLITCH ON THIS ACFT, SELECTING A NEW RWY AFTER PROGRAMMING A XING RESTR INTO THE VNAV, WILL SOMETIMES DROP THE XING RESTR. THIS IS A MAJOR TRAP WITH THIS ACFT AND I HAVE SEEN THIS OCCUR MANY TIMES. ALTHOUGH WE BOTH SHOULD HAVE CAUGHT THE EVENT, SEVERAL OTHER FACTORS CONTRIBUTED. SEVERAL FLT ATTENDANTS WERE PRESENT IN THE COCKPIT ENGAGED IN PERSONAL (NON-WORK RELATED) CONVERSATION BTWN THEMSELVES AND THE FLT DECK CREW. WE SHOULD HAVE ASKED THEM TO LEAVE AT THE TOP OF DSCNT WHEN THE WORKLOAD INCREASED. IT HAD BEEN A LONG DAY AND BOTH MYSELF AND THE CAPT WERE TIRED. (LONG DUTY DAY, W COAST TO E COAST WITH A STOP, AND A SEVERAL-HR-BREAK IN MAJOR HUB.) I FEEL IF I HAD USED BETTER CRM SKILLS, I COULD HAVE EASILY ASKED THE FLT ATTENDANTS TO LEAVE BECAUSE WE WERE GETTING BUSY.

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.