Altitude deviation.

Attributes
ACN	148372
Time
Date	199006
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : hub
State Reference	TX
Altitude	msl bound lower : 10700 msl bound upper : 11000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zhu
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 other enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 250 flight time total : 15000 flight time type : 250
ASRS Report	148372
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : commercial pilot : flight engineer pilot : instrument
Experience	flight time last 90 days : 180 flight time total : 14000 flight time type : 9500
ASRS Report	148713
Events
Anomaly	altitude deviation : overshoot non adherence : clearance other anomaly other
Independent Detector	other controllera other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	Other
Miss Distance	horizontal : 24000 vertical : 700
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation other

Narrative:

Flying from hrl to hou, cleared to descend to 10000', cross lisse (hub 250/44) at 10000'. We had been vectored off arrival and told we were to be put behind another aircraft, then vectored back toward lisse and told we would be first. Then vectored again and told we would be behind another aircraft. We were descending at approximately 4000 FPM when we were given another heading and assigned 11000'. When these instructions were given we were close to 12000', descended at greater than 4000 FPM. It was not possible to level at 11000'. We descended as low as 10600' and climbed back to 11000'. When we passed approximately 11000' we saw a company plane at 10000' and about 3 mi away. We were given the 11000' instructions too late to comply. Supplemental information from acn 148713: the autoplt indicated that it had acquired the altitude. I made the response to the center as the copilot apparently did not hear the 11000' clearance. We then made visibility contact with a company aircraft at about our 11:30 position, flying to our 11 O'clock at about 5-6 mi and below us, and commented to each other (the pilots) about the traffic. My attention was diverted from monitoring the autoplt ot the traffic. The copilot then noticed the 11000' set in the altitude selector and (as he did ont hear the clearance to level at 11000') questioned the altitude.

Original NASA ASRS Text

Title: ALT DEVIATION.

Narrative: FLYING FROM HRL TO HOU, CLRED TO DSND TO 10000', CROSS LISSE (HUB 250/44) AT 10000'. WE HAD BEEN VECTORED OFF ARR AND TOLD WE WERE TO BE PUT BEHIND ANOTHER ACFT, THEN VECTORED BACK TOWARD LISSE AND TOLD WE WOULD BE FIRST. THEN VECTORED AGAIN AND TOLD WE WOULD BE BEHIND ANOTHER ACFT. WE WERE DSNDING AT APPROX 4000 FPM WHEN WE WERE GIVEN ANOTHER HDG AND ASSIGNED 11000'. WHEN THESE INSTRUCTIONS WERE GIVEN WE WERE CLOSE TO 12000', DSNDED AT GREATER THAN 4000 FPM. IT WAS NOT POSSIBLE TO LEVEL AT 11000'. WE DSNDED AS LOW AS 10600' AND CLBED BACK TO 11000'. WHEN WE PASSED APPROX 11000' WE SAW A COMPANY PLANE AT 10000' AND ABOUT 3 MI AWAY. WE WERE GIVEN THE 11000' INSTRUCTIONS TOO LATE TO COMPLY. SUPPLEMENTAL INFO FROM ACN 148713: THE AUTOPLT INDICATED THAT IT HAD ACQUIRED THE ALT. I MADE THE RESPONSE TO THE CENTER AS THE COPLT APPARENTLY DID NOT HEAR THE 11000' CLRNC. WE THEN MADE VIS CONTACT WITH A COMPANY ACFT AT ABOUT OUR 11:30 POS, FLYING TO OUR 11 O'CLOCK AT ABOUT 5-6 MI AND BELOW US, AND COMMENTED TO EACH OTHER (THE PLTS) ABOUT THE TFC. MY ATTN WAS DIVERTED FROM MONITORING THE AUTOPLT OT THE TFC. THE COPLT THEN NOTICED THE 11000' SET IN THE ALT SELECTOR AND (AS HE DID ONT HEAR THE CLRNC TO LEVEL AT 11000') QUESTIONED THE ALT.

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.