A320 flight crew reports receiving a TCAS RA while descending to 7;000 feet with the engines at flig...

Attributes
ACN	1238520
Time
Date	201502
Local Time Of Day	0601-1200
Place
Locale Reference	D01.TRACON
State Reference	CO
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	Final Approach
Flight Plan	IFR
Component
Aircraft Component	Turbine Engine
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 150 Flight Crew Total 25000 Flight Crew Type 14000
Person 2
Function	First Officer Pilot Not Flying
Experience	Flight Crew Last 90 Days 180 Flight Crew Total 9000 Flight Crew Type 5000
Events
Anomaly	Aircraft Equipment Problem Less Severe Conflict Airborne Conflict

Narrative:

We were on a visual approach just about to intercept the localizer. I was hand flying the airplane with auto-throttles off. Just as we were approaching chola; I observed a pop up TCAS target at 1130 position 500 feet below us in the climb. I notified the first officer of the target and he reported it to ATC. Simultaneously we got an aggressive RA to climb; climb now and ATC gave us a traffic alert climb immediately! I went to toga (take off/go-around) thrust from flight idle and began to follow the RA guidance on the vvi. To my and the first officer's surprise; the thrust took 4 to 5 seconds to go to toga!!! Recognizing the delay in thrust response; I started a right turn away from the TCAS target to evade the target laterally. The first officer reported to ATC we were in a TCAS climb and called for me to keep climbing and confirmed I had toga selected. As thrust finally went to toga and with the turn away from the target; we began to aggressively climb and the RA conflict resolved. We simply could not believe how long it took for the thrust to go to toga! We wrote up the airplane thrust system upon arrival at the gate in den. The aircraft was taken out of service to test the thrust system. I called approach and they concurred what data that had at the time indicated we had 200 feet and 1 mile separation.

Original NASA ASRS Text

Title: A320 flight crew reports receiving a TCAS RA while descending to 7;000 feet with the engines at flight idle. After selecting Takeoff/Go-Around (TOGA) mode to evade; a 4-5 second delay is experienced before TOGA thrust is achieved.

Narrative: We were on a visual approach just about to intercept the localizer. I was hand flying the airplane with auto-throttles OFF. Just as we were approaching CHOLA; I observed a pop up TCAS target at 1130 position 500 feet below us in the climb. I notified the First Officer of the target and he reported it to ATC. Simultaneously we got an aggressive RA to Climb; Climb NOW and ATC gave us a traffic alert climb immediately! I went to TOGA (Take Off/Go-Around) thrust from flight idle and began to follow the RA guidance on the VVI. To my and the first officer's surprise; the thrust took 4 to 5 seconds to go to TOGA!!! Recognizing the delay in thrust response; I started a right turn away from the TCAS target to evade the target laterally. The FO reported to ATC we were in a TCAS climb and called for me to keep climbing and confirmed I had TOGA selected. As thrust finally went to TOGA and with the turn away from the target; we began to aggressively climb and the RA conflict resolved. We simply could not believe how long it took for the thrust to go to TOGA! We wrote up the airplane thrust system upon arrival at the gate in DEN. The aircraft was taken out of service to test the thrust system. I called approach and they concurred what data that had at the time indicated we had 200 feet and 1 mile separation.

Data retrieved from NASA's ASRS site 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.

A320 flight crew reports receiving a TCAS RA while descending to 7;000 feet with the engines at flight idle. After selecting takeoff/go-around (toga) mode to evade; a 4-5 second delay is experienced before toga thrust is achieved.