Air carrier X descent through occupied altitude received TCASII TA RA with climbing B737.

Attributes
ACN	262662
Time
Date	199401
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : bna
State Reference	TN
Altitude	msl bound lower : 5000 msl bound upper : 6000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : bna
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 121
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 170 flight time total : 5000 flight time type : 900
ASRS Report	262662
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	altitude deviation : undershoot conflict : airborne less severe non adherence : clearance non adherence : published procedure
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	controller : issued new clearance other
Consequence	Other
Miss Distance	vertical : 1000
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

Air carrier X being vectored for an ILS approach for runway 2L at bna. Nashville approach on frequency 120.6 issued a descent to us from 6000 ft to 4000 ft and gave us a frequency change to 133.0 (final controller). Before initiating contact we got a TCASII TA. I saw, on TCASII, an aircraft climbing through 4000 ft. I initiated contact on 133.0, we stayed at 6000 but I told the controller that we were cleared to 4000 ft. The controller immediately told us to maintain 6000 and advised us of a 737 at our 10-11 O'clock climbing to 5000. As this was occurring we received a TCASII RA (resolution advisory) telling us to descend at 2000 FPM. Had we followed this we would have hit the 737. By this time we had the 737 in sight and there was no conflict. The TCASII tested normal after landing.

Original NASA ASRS Text

Title: ACR X DSCNT THROUGH OCCUPIED ALT RECEIVED TCASII TA RA WITH CLBING B737.

Narrative: ACR X BEING VECTORED FOR AN ILS APCH FOR RWY 2L AT BNA. NASHVILLE APCH ON FREQ 120.6 ISSUED A DSCNT TO US FROM 6000 FT TO 4000 FT AND GAVE US A FREQ CHANGE TO 133.0 (FINAL CTLR). BEFORE INITIATING CONTACT WE GOT A TCASII TA. I SAW, ON TCASII, AN ACFT CLBING THROUGH 4000 FT. I INITIATED CONTACT ON 133.0, WE STAYED AT 6000 BUT I TOLD THE CTLR THAT WE WERE CLRED TO 4000 FT. THE CTLR IMMEDIATELY TOLD US TO MAINTAIN 6000 AND ADVISED US OF A 737 AT OUR 10-11 O'CLOCK CLBING TO 5000. AS THIS WAS OCCURRING WE RECEIVED A TCASII RA (RESOLUTION ADVISORY) TELLING US TO DSND AT 2000 FPM. HAD WE FOLLOWED THIS WE WOULD HAVE HIT THE 737. BY THIS TIME WE HAD THE 737 IN SIGHT AND THERE WAS NO CONFLICT. THE TCASII TESTED NORMAL AFTER LNDG.

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.