ZOB controller is advised by B737 of TCASII RA maneuver when in holding.

Attributes
ACN	591040
Time
Date	200308
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : dxo.vor
State Reference	MI
Altitude	msl single value : 18000
Environment
Weather Elements	Thunderstorm
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zau.artcc artcc : zob.artcc
Operator	common carrier : air carrier
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	cruise : holding
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zob.artcc artcc : zau.artcc
Operator	common carrier : air carrier
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	cruise : holding
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	other personnel other
Qualification	controller : radar pilot : instrument
Experience	controller radar : 2 flight time total : 300
ASRS Report	591040
Person 2
Affiliation	government : faa
Function	controller : radar
Events
Anomaly	conflict : airborne critical non adherence : published procedure non adherence : required legal separation
Independent Detector	aircraft equipment : tcas
Resolutory Action	none taken : detected after the fact
Consequence	faa : investigated
Miss Distance	horizontal : 16200 vertical : 800
Supplementary
Problem Areas	Environmental Factor ATC Human Performance
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

We were in the hold for detroit and had just sent 2 aircraft in as pathfinders. One aircraft said he could only take one more turn or he would have to divert, so coordination was being done to assist him. At the same time, additional coordination was being done with ZAU. There was some frequency congestion and an aircraft said he was responding to an RA. Looking at the radar, the aircraft targets appeared to be vertically separated. Although there was a loss of separation, the radar controller did a great job working numerous aircraft in a very complex situation.

Original NASA ASRS Text

Title: ZOB CTLR IS ADVISED BY B737 OF TCASII RA MANEUVER WHEN IN HOLDING.

Narrative: WE WERE IN THE HOLD FOR DETROIT AND HAD JUST SENT 2 ACFT IN AS PATHFINDERS. ONE ACFT SAID HE COULD ONLY TAKE ONE MORE TURN OR HE WOULD HAVE TO DIVERT, SO COORD WAS BEING DONE TO ASSIST HIM. AT THE SAME TIME, ADDITIONAL COORD WAS BEING DONE WITH ZAU. THERE WAS SOME FREQ CONGESTION AND AN ACFT SAID HE WAS RESPONDING TO AN RA. LOOKING AT THE RADAR, THE ACFT TARGETS APPEARED TO BE VERTLY SEPARATED. ALTHOUGH THERE WAS A LOSS OF SEPARATION, THE RADAR CTLR DID A GREAT JOB WORKING NUMEROUS ACFT IN A VERY COMPLEX SIT.

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.