TCASII causes medium large transport to climb 1000 ft above assigned altitude.

Attributes
ACN	234612
Time
Date	199302
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : atl
State Reference	GA
Altitude	msl bound lower : 26000 msl bound upper : 27000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : ztl tower : cha
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	cruise other
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	climbout : intermediate altitude cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : cfi pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 225 flight time total : 7500 flight time type : 3000
ASRS Report	234612
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	altitude deviation : excursion from assigned altitude
Independent Detector	aircraft equipment other aircraft equipment : unspecified other controllera
Resolutory Action	none taken : unable
Consequence	Other

Narrative:

While cruising at FL260 we received a TCASII RA. First officer began an immediate climb as directed by TCASII. ATC then advised us of traffic (an medium large transport) at 12 O'clock, climbing to FL250. ATC asked medium large transport to confirm leveling at FL250. They indicated that they were. Did not see medium large transport until they went by in close at about 9 O'clock position. By that time we were at FL270 and TCASII indicated the event was over. We followed RA as per procedure. Apparently the TCASII sensed a high rate of climb by medium large transport aircraft and reacted by issuing us an RA.

Original NASA ASRS Text

Title: TCASII CAUSES MLG TO CLB 1000 FT ABOVE ASSIGNED ALT.

Narrative: WHILE CRUISING AT FL260 WE RECEIVED A TCASII RA. FO BEGAN AN IMMEDIATE CLB AS DIRECTED BY TCASII. ATC THEN ADVISED US OF TFC (AN MLG) AT 12 O'CLOCK, CLBING TO FL250. ATC ASKED MLG TO CONFIRM LEVELING AT FL250. THEY INDICATED THAT THEY WERE. DID NOT SEE MLG UNTIL THEY WENT BY IN CLOSE AT ABOUT 9 O'CLOCK POS. BY THAT TIME WE WERE AT FL270 AND TCASII INDICATED THE EVENT WAS OVER. WE FOLLOWED RA AS PER PROC. APPARENTLY THE TCASII SENSED A HIGH RATE OF CLB BY MLG ACFT AND REACTED BY ISSUING US AN RA.

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.