Operational error between air carrier X and air carrier Y potential conflict.

Attributes
ACN	291952
Time
Date	199412
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : den
State Reference	CO
Altitude	msl bound lower : 25000 msl bound upper : 25000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdv
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	cruise other descent other
Flight Plan	IFR
Aircraft 2
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	other : unknown
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : flight engineer pilot : commercial pilot : atp
Experience	flight time last 90 days : 210 flight time total : 14000 flight time type : 6500
ASRS Report	291952
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	other anomaly other
Independent Detector	other flight crewa
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Air carrier X was on descent into denver and given a clearance to descend to FL240. Upon descending through FL252 at approximately 3500 FPM rate of descent (we were told to expedite descent through FL250) we were given clearance to level at FL250. We told controller we would be unable due to fact we were already descending through FL247 or FL246. His reply was level at FL250. We leveled approximately FL245 and climbed back to FL250. On TCASII we noticed possible conflicting traffic at FL240. I do not believe we were any closer than 5 mi and/or 500 ft from him. Controller was busy and appeared not to realize the other traffic at FL240 and when he did he appeared to be surprised and a bit panicky in his approach to conflict resolution. Controllers have to realize we don't fly elevators. It gets very frustrating, trying to comply with impossible vectors, speeds and altitude requirements when possible conflicts occur.

Original NASA ASRS Text

Title: OPERROR BTWN ACR X AND ACR Y POTENTIAL CONFLICT.

Narrative: ACR X WAS ON DSCNT INTO DENVER AND GIVEN A CLRNC TO DSND TO FL240. UPON DSNDING THROUGH FL252 AT APPROX 3500 FPM RATE OF DSCNT (WE WERE TOLD TO EXPEDITE DSCNT THROUGH FL250) WE WERE GIVEN CLRNC TO LEVEL AT FL250. WE TOLD CTLR WE WOULD BE UNABLE DUE TO FACT WE WERE ALREADY DSNDING THROUGH FL247 OR FL246. HIS REPLY WAS LEVEL AT FL250. WE LEVELED APPROX FL245 AND CLBED BACK TO FL250. ON TCASII WE NOTICED POSSIBLE CONFLICTING TFC AT FL240. I DO NOT BELIEVE WE WERE ANY CLOSER THAN 5 MI AND/OR 500 FT FROM HIM. CTLR WAS BUSY AND APPEARED NOT TO REALIZE THE OTHER TFC AT FL240 AND WHEN HE DID HE APPEARED TO BE SURPRISED AND A BIT PANICKY IN HIS APCH TO CONFLICT RESOLUTION. CTLRS HAVE TO REALIZE WE DON'T FLY ELEVATORS. IT GETS VERY FRUSTRATING, TRYING TO COMPLY WITH IMPOSSIBLE VECTORS, SPDS AND ALT REQUIREMENTS WHEN POSSIBLE CONFLICTS OCCUR.

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.