2010-04 · NASA ASRS report 883545
P50 described a conflict event when an air carrier departure reportedly responded to a TCAS warning and climbed above assigned altitude causing a close encounter with issued traffic; faulty aircraft equipment listed by flight crew as possible causal factors.
I was working 'S' Departure and had 2 surveillance aircraft on frequency in my airspace. I had Government Y just off the departure end of Sky Harbor at 8;500 and Government Z about 5-15 east of PHX at 10;500. Government Z was orbiting but also moving between 5 and 20 miles east of the PXR VORTAC. I had the usual noon time departure push and would first stop all the departures at 8;000 for Government Y and then after they cleared climbed them to 10;000 for Government Z. After passing Government Z I would climb them to FL210. If I observed any of the departures getting close to either aircraft I would issue a traffic call to both aircraft involved. About 20 minutes into the push I had Air Carrier X; a TFD2 departure and I issued him a turn to 190 to join the departure and climbed to 10;000. He acknowledged the altitude and then I advised him of the traffic that was orbiting at 10;500. He responded with; 'Roger'; and I advised Government Z of the traffic and he also acknowledged the traffic. I went back to looking at my other traffic and then back to Air Carrier X and Government Z to see Air Carrier X climbing right through Government Z. After they passed I told Government Z I guess he climbed on me; and the pilot responded with 'that was awfully close' or something to that effect; but he appeared to be pretty shaken up. I then went to Air Carrier X and again told him he was assigned 10;000 for the traffic and he said 'TCAS climb; we need a number to call!' I again told him to turn to a heading to join the departure as he didn't take my initial turn and then went back to working my other aircraft and then just before shipping Air Carrier X to ZAB; I gave him our phone number. Our Supervisor was behind me during this and he took the flight progress strip from me and then went back and listened to and watched the playback on the computer. I worked another 20 minutes or so and finished up the departure push and after it was all done I went back to Government Z and asked him if he heard what Air Carrier X said about a TCAS climb; and he said he did; but he said he saw the aircraft and even though his TCAS was telling him to climb; he descended as he thought it was the more prudent move to do. I told him again that I was sorry it happened and he said 'no sweat not your fault'. I then was relived from position and walked back to find out the Supervisor said he listened and watched the replay and I was correct in everything I did; Air Carrier X acknowledged the climb to 10;000 and then even though he was already at 8;000 he started climbing very rapidly even though he was only going up 2000 feet. He was at 9600 and the next sweep he was at 10300 then 10600 and then 11100 as he was passing Government Z. The targets and data tags appeared to merge on my scope and then they were 500 feet apart after they passed. Recommendation; my most prudent move would have been to stop the departures at 9000 feet instead of 10;000 to allow a 1500 foot buffer; as I usually do with unverified VFR altitudes but I had to get these TFD departures up and above the arrival traffic that was descending out 11;000 and I thought that since I was talking to both and both aircraft knew about each other that it would be OK to use 10;000.
At takeoff we were cleared to 7000 as usual then to 8000; then to 10000. I don't remember if ATC pointed out any traffic to us or not. I do remember getting a TCAS TA and looking for traffic at around 10 to 11 o'clock position. I'm guessing in 4 seconds tops we got a RA climb. I kicked off the auto pilot selected my own FD off and said 'FD off.' I was pitching up and looking to pitch into the green on my V/S indicator. As I looked down to find the green band I couldn't find it. It was a bright sunny day heading somewhat southerly and the PFD (primary flight display) was a little hard to see after just having been looking outside. I could see the red at the top of the V/S but not the green band. I was surprised to not see the green band and thought maybe that it was commanding such an aggressive climb that the green band was buried at the top of the V/S and that as I pitched up more I would see it. The time from the TCAS TA to the RA was shorter than either the First Officer or I have ever seen at anytime in our careers suggesting to me the large climb I thought the TCAS was giving me was probably real. I never did see the green band. As I glanced up I saw a regional jet just left of dead center in the windshield. I gave a full left side stick command and we just passed behind him. Right at this critical time ATC became aware of our situation and asked our altitude which was now around 11000. Somewhere in the climb; either just before the RA or more likely during the RA; I remember ATC calling out an Airbus at 8800 to some other traffic and thinking he was probably talking about us. As the Controller recognized the near miss he told us we were only cleared to 10000 and to get back down to it. We acknowledged that and told him we were responding to a RA. There was no time to call it in earlier due to radio traffic. The Controller asked some other aircraft if he saw us or maybe had seen us. Just as we were getting close to 10000 the Controller gave us a climb to 21000 (pretty sure) and a turn to 210 (not real sure) to join the TFD 340 radial and the departure SID. Of course this event shook us up and I reengaged the auto pilot and FD and turned and pulled all the knobs to comply but the aircraft didn't respond. I pulled them all again careful to verify on the FMA what I had done was correct but it still had no effect. I kicked off the auto pilot and hand flew to comply with our clearance and asked the First Officer to see if he could get the auto pilot and FD to work. He tried the same things I had to no avail but cycled the FD and got it working again. We climbed with all the automation. Our clearance was to intercept the TFD 340 but on the heading we were on we were going to instead join the SID southeast of TFD a couple of miles. My First Officer asked the Controller for a phone number he could call to find out what had just happened. In cruise my First Officer and I compared stories to see what had happened. My First Officer said he never heard the TCAS say to climb. He heard it say some RA which one he wasn't sure of. He also said initially he thought I was wrong to be climbing and was about to say something but when he looked to verify before telling me; he saw something strange on the displays so that he couldn't be sure of what the TCAS was telling us to do. Neither the First Officer or myself; remember acknowledging any traffic in sight except maybe the regional jet after we just missed him. Let me address fully here the possibility I went the wrong way to a RA. It is of course possible I heard 'climb' wrong and pulled up when I should have done something else. I can certainly hear things wrong sometimes. This would make so much sense given our step climb situation and my never seeing the green band during the pitch up. This whole thing could be that simple. I don't believe that is what happened but of course it is possible. During my pitch up climb; the top of the V/S tape was solid red and I thought it went all the wayto the bottom; but I can't say that with certainty as I was focused on the top of the V/S looking for the green band. I know that if you have a monitor V/S situation there might not be a green area and you should simply avoid the red. In my mind I heard 'climb' and was expecting a green band to pitch to. If I indeed misheard the climb command and pitched up into traffic wouldn't the TCAS take that into account and issue new descending commands? We never heard anything else out of the TCAS after the first command whatever that command really was. No 'end of conflict' or anything. We weren't panicky at all. When we got the RA we just started taking care of business. What was so confusing on the display that the First Officer couldn't determine whether I was right or wrong to pitch up even after having the initial impression that up was wrong? This next one I don't believe had any bearing. After our PHX arrival; I called ATC and they indicated they needed to find out more information and would call back in a few minutes which he did. After I gave him all the information he needed he told me he had carefully reviewed the tapes 3 times even in slow motion and told me that we had had 2 government aircraft at 8500 and 10500 and that one of those (I assume the one that was at 10500) was the one that we just missed. ATC said that PHX ATC is very familiar with these aircraft as they work with them all the time. ATC said we did not come close to any regional jet; only the government aircraft. I asked if the government aircraft could have been painted in Air Carrier colors and he said he didn't know but that the aircraft were not regional jets. Again what aircraft did what; that caused our TCAS to go from a TA to a RA in less than 4 seconds? To whom did ATC point out an Airbus to at 8800 as we were near 8800? I'm just curious. I believe our TCAS malfunctioned. I believe later our auto pilot and FD malfunctioned. [It was] probably just a glitch; an Airbus-ism. I believe that PHX ATC was wrong when they said we did not come close to a regional jet. In conclusion I'm not sure what happened or what caused it. In my mind I got a RA to climb and I responded. In the next 10 seconds there was confusing information and circumstances making it impossible for me to know what all transpired.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.
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