An air carrier large transport climbed in response to a TCASII command.

Attributes
ACN	240005
Time
Date	199304
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : rod
State Reference	OH
Altitude	msl bound lower : 33000 msl bound upper : 33900
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zid
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	cruise other
Flight Plan	IFR
Aircraft 2
Operator	other
Make Model Name	Fighter
Flight Phase	climbout : intermediate altitude cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 190 flight time total : 8000 flight time type : 3500
ASRS Report	240005
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 260 flight time total : 14500 flight time type : 2330
ASRS Report	240328
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course flight crew : overcame equipment problem flight crew : took evasive action
Consequence	Other
Miss Distance	vertical : 2000
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

We responded to a TCASII RA which commanded a climb at a minimum of 1500 FPM. We complied and climbed to 33900 ft, at which time the TCASII commanded 'monitor vertical speed.' when the conflict was over, we descended back to 33000 ft. Our TCASII had detected an aircraft with a very high rate of climb, which if it continued at its rate of climb, would enter our TCASII warning area. ATC should advise when a high performance aircraft is approaching at a high rate of climb or descent because TCASII will always respond as if the intruder continues on its present vertical speed. In this case, the intruder leveled off at 31000 ft, but TCASII had no way of predicting that. Supplemental information from acn 240328: we returned to 33000 ft. TCASII showed the traffic to be at our 8 O'clock position and 2100 ft below us. We checked the position and saw a military jet fgt. Just prior to our deviation I asked center if he showed any traffic for us. He said 'no' then said he just had a pop-up.

Original NASA ASRS Text

Title: AN ACR LGT CLBED IN RESPONSE TO A TCASII COMMAND.

Narrative: WE RESPONDED TO A TCASII RA WHICH COMMANDED A CLB AT A MINIMUM OF 1500 FPM. WE COMPLIED AND CLBED TO 33900 FT, AT WHICH TIME THE TCASII COMMANDED 'MONITOR VERT SPD.' WHEN THE CONFLICT WAS OVER, WE DSNDED BACK TO 33000 FT. OUR TCASII HAD DETECTED AN ACFT WITH A VERY HIGH RATE OF CLB, WHICH IF IT CONTINUED AT ITS RATE OF CLB, WOULD ENTER OUR TCASII WARNING AREA. ATC SHOULD ADVISE WHEN A HIGH PERFORMANCE ACFT IS APCHING AT A HIGH RATE OF CLB OR DSCNT BECAUSE TCASII WILL ALWAYS RESPOND AS IF THE INTRUDER CONTINUES ON ITS PRESENT VERT SPD. IN THIS CASE, THE INTRUDER LEVELED OFF AT 31000 FT, BUT TCASII HAD NO WAY OF PREDICTING THAT. SUPPLEMENTAL INFO FROM ACN 240328: WE RETURNED TO 33000 FT. TCASII SHOWED THE TFC TO BE AT OUR 8 O'CLOCK POS AND 2100 FT BELOW US. WE CHKED THE POS AND SAW A MIL JET FGT. JUST PRIOR TO OUR DEV I ASKED CTR IF HE SHOWED ANY TFC FOR US. HE SAID 'NO' THEN SAID HE JUST HAD A POP-UP.

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.