Air carrier widebody transport altitude deviation undershot during descent crossing restriction not ...

Attributes
ACN	132406
Time
Date	198912
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : gdm airport : bos
State Reference	CT
Altitude	msl bound lower : 11000 msl bound upper : 12500
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent other other
Route In Use	enroute : on vectors enroute airway : bos
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : commercial pilot : instrument pilot : flight engineer
Experience	flight time last 90 days : 100 flight time total : 17000
ASRS Report	132406
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	altitude deviation : crossing restriction not met altitude deviation : undershoot non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	none taken : unable
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

The flight was airlines flight, 12/89, lax-bos. My clearance was to hold gdm, left-hand turns, FL190, 20 NM legs. Upon approaching gdm, I was given the following clearance: maintain FL190 to gdm, cross bronc at 11000'/250 KTS. Initiated descent at gdm. Once into descent, I realized the aircraft's inability to lose 8000' in 15 NM. In my first attempt to advise the controller, I was stepped on by radio traffic. The second transmission got through where I advised unable 11000' bronc. The controller replied with a clearance of 11000'/250 KTS. The altitude bust was in excess of 1000'. At an airspeed of 250 KIAS (300 KTS TAS) the 15 NM is covered in 2 1/2 mins, which means that my rate of descent would be 3200 FPM. This does not account for the time to initiate and stop the descent. During the descent, my speed was in excess of 300 tax, the time lapse was under 2 min. At bronc I had slowed to 250 KTS. Tail wind component was between 40-70 KTS during descent. The clearance was apparently outside the parameters of the aircraft.

Original NASA ASRS Text

Title: ACR WDB ALT DEVIATION UNDERSHOT DURING DESCENT CROSSING RESTRICTION NOT MET.

Narrative: THE FLT WAS AIRLINES FLT, 12/89, LAX-BOS. MY CLRNC WAS TO HOLD GDM, LEFT-HAND TURNS, FL190, 20 NM LEGS. UPON APCHING GDM, I WAS GIVEN THE FOLLOWING CLRNC: MAINTAIN FL190 TO GDM, CROSS BRONC AT 11000'/250 KTS. INITIATED DSCNT AT GDM. ONCE INTO DSCNT, I REALIZED THE ACFT'S INABILITY TO LOSE 8000' IN 15 NM. IN MY FIRST ATTEMPT TO ADVISE THE CTLR, I WAS STEPPED ON BY RADIO TFC. THE SECOND XMISSION GOT THROUGH WHERE I ADVISED UNABLE 11000' BRONC. THE CTLR REPLIED WITH A CLRNC OF 11000'/250 KTS. THE ALT BUST WAS IN EXCESS OF 1000'. AT AN AIRSPD OF 250 KIAS (300 KTS TAS) THE 15 NM IS COVERED IN 2 1/2 MINS, WHICH MEANS THAT MY RATE OF DSCNT WOULD BE 3200 FPM. THIS DOES NOT ACCOUNT FOR THE TIME TO INITIATE AND STOP THE DSCNT. DURING THE DSCNT, MY SPD WAS IN EXCESS OF 300 TAX, THE TIME LAPSE WAS UNDER 2 MIN. AT BRONC I HAD SLOWED TO 250 KTS. TAIL WIND COMPONENT WAS BTWN 40-70 KTS DURING DSCNT. THE CLRNC WAS APPARENTLY OUTSIDE THE PARAMETERS OF THE ACFT.

Data retrieved from NASA's ASRS site as of August 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.

Air carrier widebody transport altitude deviation undershot during descent crossing restriction not met.