Medium large transport air carrier undershoots crossing restriction when operating on it's flight gu...

Attributes
ACN	211391
Time
Date	199205
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : pit
State Reference	PA
Altitude	msl bound lower : 11000 msl bound upper : 11200
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	arrival : profile descent enroute airway : pit
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : cfi pilot : commercial pilot : flight engineer pilot : instrument pilot : atp
Experience	flight time last 90 days : 250 flight time total : 20000 flight time type : 300
ASRS Report	211391
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	altitude deviation : crossing restriction not met altitude deviation : undershoot non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Was given a descent and crossing restriction at cutta 10000 ft. I was using all automatic system in profile descent mode. Center asked at some point if we would make cutta at 10000. The automatic system showed 750 ft low on profile however manual/mental calculations said no way. First officer made numerous attempts to advise via radio with no acknowledgement from center -- who finally gave a frequency change to approach (approximately 2-3 mi after cutta). We were cleared by vector to the airport (approximately 150 degrees) and 10000 ft. I believe we crossed cutta at 11200 ft and 4000 FPM to cvc and 10000 ft approximately 15 seconds after crossing cutta. What can I say other than never trust the medium large transport flight guidance system. On another note, ATC does not respond or late (past 10-12 months) when crews are in need of help (amendment) to clearance or give clearance too late for crews to accommodate (especially) if they don't flat out dive for the ground immediately.

Original NASA ASRS Text

Title: MLG ACR UNDERSHOOTS XING RESTRICTION WHEN OPERATING ON IT'S FLT GUIDANCE SYS.

Narrative: WAS GIVEN A DSCNT AND XING RESTRICTION AT CUTTA 10000 FT. I WAS USING ALL AUTO SYS IN PROFILE DSCNT MODE. CTR ASKED AT SOME POINT IF WE WOULD MAKE CUTTA AT 10000. THE AUTO SYS SHOWED 750 FT LOW ON PROFILE HOWEVER MANUAL/MENTAL CALCULATIONS SAID NO WAY. FO MADE NUMEROUS ATTEMPTS TO ADVISE VIA RADIO WITH NO ACKNOWLEDGEMENT FROM CTR -- WHO FINALLY GAVE A FREQ CHANGE TO APCH (APPROX 2-3 MI AFTER CUTTA). WE WERE CLRED BY VECTOR TO THE ARPT (APPROX 150 DEGS) AND 10000 FT. I BELIEVE WE CROSSED CUTTA AT 11200 FT AND 4000 FPM TO CVC AND 10000 FT APPROX 15 SECONDS AFTER XING CUTTA. WHAT CAN I SAY OTHER THAN NEVER TRUST THE MLG FLT GUIDANCE SYS. ON ANOTHER NOTE, ATC DOES NOT RESPOND OR LATE (PAST 10-12 MONTHS) WHEN CREWS ARE IN NEED OF HELP (AMENDMENT) TO CLRNC OR GIVE CLRNC TOO LATE FOR CREWS TO ACCOMMODATE (ESPECIALLY) IF THEY DON'T FLAT OUT DIVE FOR THE GND IMMEDIATELY.

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.

Medium large transport air carrier undershoots crossing restriction when operating on it's flight guidance system.