Air carrier X possible less than standard separation with unknown aircraft TCASII RA.

Attributes
ACN	194599
Time
Date	199111
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : fwa
State Reference	IN
Altitude	msl bound lower : 21000 msl bound upper : 21000
Environment
Flight Conditions	IMC
Light	Dawn
Aircraft 1
Controlling Facilities	artcc : zau
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	descent 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 : 225 flight time total : 28600 flight time type : 18000
ASRS Report	194599
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 11000 flight time type : 5000
ASRS Report	194597
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	controller : issued new clearance other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Air carrier X requested a descent to a lower altitude. ATC cleared our flight from FL230 to FL210. Initial descent rate of 2000 FPM was set. At approximately FL218 ATC gave us a 30 degree left turn, descend to FL190 and call out of FL210. As we called out of FL210 we heard another aircraft state he was climbing to resolve a TCASII conflict. The reason for this report is to cover a possible loss of separation. Contributing factor: controller was covering too many aircraft and too many frequencys. Supplemental information from acn 194597: in turbulence at FL230, requested descent. Center cleared us to FL210. In descent, controller had us turn left to 090 degree heading and cleared us to FL190 and asked us to expedite. PF increased rate of descent. Controller asked us to report out of FL210 as we were passing that altitude and we did. Soon after we heard another aircraft report a TCASII RA. Controller told other aircraft that we reported out of FL210. Nothing more was said and ATC handed us off to ZID.

Original NASA ASRS Text

Title: ACR X POSSIBLE LTSS WITH UNKNOWN ACFT TCASII RA.

Narrative: ACR X REQUESTED A DSCNT TO A LOWER ALT. ATC CLRED OUR FLT FROM FL230 TO FL210. INITIAL DSCNT RATE OF 2000 FPM WAS SET. AT APPROX FL218 ATC GAVE US A 30 DEG L TURN, DSND TO FL190 AND CALL OUT OF FL210. AS WE CALLED OUT OF FL210 WE HEARD ANOTHER ACFT STATE HE WAS CLBING TO RESOLVE A TCASII CONFLICT. THE REASON FOR THIS RPT IS TO COVER A POSSIBLE LOSS OF SEPARATION. CONTRIBUTING FACTOR: CTLR WAS COVERING TOO MANY ACFT AND TOO MANY FREQS. SUPPLEMENTAL INFO FROM ACN 194597: IN TURB AT FL230, REQUESTED DSCNT. CENTER CLRED US TO FL210. IN DSCNT, CTLR HAD US TURN L TO 090 DEG HDG AND CLRED US TO FL190 AND ASKED US TO EXPEDITE. PF INCREASED RATE OF DSCNT. CTLR ASKED US TO RPT OUT OF FL210 AS WE WERE PASSING THAT ALT AND WE DID. SOON AFTER WE HEARD ANOTHER ACFT RPT A TCASII RA. CTLR TOLD OTHER ACFT THAT WE RPTED OUT OF FL210. NOTHING MORE WAS SAID AND ATC HANDED US OFF TO ZID.

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.