CL65 flight crew reacts to TCASII RA near hmv.

Attributes
ACN	456551
Time
Date	199912
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	navaid : hmv.vortac
State Reference	TN
Altitude	msl bound lower : 23000 msl bound upper : 24000
Environment
Flight Conditions	IMC
Weather Elements	Ice Turbulence
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zid.artcc
Operator	common carrier : air carrier
Make Model Name	Challenger CL604
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial pilot : multi engine pilot : cfi
Experience	flight time last 90 days : 170 flight time total : 3500 flight time type : 1000
ASRS Report	456551
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance non adherence other other spatial deviation
Independent Detector	aircraft equipment : tcas other flight crewa
Resolutory Action	flight crew : returned to assigned altitude
Miss Distance	horizontal : 15000 vertical : 1000
Supplementary
Problem Areas	ATC Human Performance Airspace Structure FAA
Primary Problem	Ambiguous

Narrative:

At approximately XA10 at FL240 in cruise in IMC, we were given a TA. Pulling up the TCASII page showed traffic above, descending rapidly, who (as we found out later) were cleared down to FL250. As traffic came within 3 mi first officer us horizontally and at such a rapid descent rate, it gave us an RA which we responded to. We nosed over, leveled off at FL230. Called ATC and advised them. Then we returned back to FL240.

Original NASA ASRS Text

Title: CL65 FLC REACTS TO TCASII RA NEAR HMV.

Narrative: AT APPROX XA10 AT FL240 IN CRUISE IN IMC, WE WERE GIVEN A TA. PULLING UP THE TCASII PAGE SHOWED TFC ABOVE, DSNDING RAPIDLY, WHO (AS WE FOUND OUT LATER) WERE CLRED DOWN TO FL250. AS TFC CAME WITHIN 3 MI FO US HORIZLY AND AT SUCH A RAPID DSCNT RATE, IT GAVE US AN RA WHICH WE RESPONDED TO. WE NOSED OVER, LEVELED OFF AT FL230. CALLED ATC AND ADVISED THEM. THEN WE RETURNED BACK TO FL240.

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.