"Please read my analysis of the decision problem presented to the Bakshirian crew at Überlingen. They were faced with an "intruder" at 10 o'clock which they saw, and an unknown conflict at 2 o'clock which they didn't see, and for which they had an advisory to descend (that is, he was at or above their altitude).
What would you do? Climb towards another conflicting aircraft that you don't see but ATC does? Or avoid him, descend towards an aircraft that you do see, and hope to avoid him using visual means?
Please give some good reasons for your answer that will also be good reasons for any other pilot in this situation."
Reading part of the report quickly, I couldn't find where this second intruder is mentioned. Please show the chapter for me.
Section 2.2.2 says that the DHL plane was to the left of the 154 and first seen on TCAS at 27 miles. The board says in this chapter that the crew knew that the intruder aircraft was at their altitude based on the captain saying "Here it is showing zero". The 154 crew then got a traffic alert and after being instructed to descend by ATC, they got a climb RA. They followed ATC and the rest is history.
Faced with your scenario above, I would follow the RA. It is most surely correct that it is giving accurate information about a high risk of conflict. Ignoring an RA because there are some other lights out there is very risky. There are many optical illusions, especially at night and those other lights may be very far off or not even an airplane. I would suggest that the risk of a collision with that aircraft is likely less and even if you were to intentionally try to hit it you would most likely miss. On the other hand thinking that you can visually avoid a conflict by going against the RA can lead to disaster as this JAL captain nearly found out, by almost creating the world's worst aviation disaster.
http://aviation-safety.net/database/...?id=20010131-3
As an example of an illusion of a risk of collision leading to evasive action that actually caused a collision leading to airline passenger deaths, read this.
"TWA Boeing 707 N748TW and Eastern Constellation N6218C approached Carmel VORTAC at FL110 resp. FL100. Due to an optical illusion caused by the up-slope effect of cloud tops, the Eastern 1st officer thought they were on collision course with the TWA jet. He pulled up the Constellation. The reaction of the TWA crew was to roll to the right, followed by a left roll down. Both aircraft collided. The Boeing made a safe landing.
PROBABLE CAUSE: "Misjudgement of altitude separation by the crew of EA853 because of an optical illusion created by the up-slope effect of cloud tops resulting in an evasive manoeuvre by the EA853 crew and a reactionary evasive manoeuvre by the TW42 crew.""
http://www.prop-liners.com/midair.htm
Avoid the danger that is being warned to you by reliable technology, sometimes it is dangerous to try to outthink it all. In the end, its an odds game with TCAS in your favour.
As an interesting tidbit in this report, read section 1.1.2. The aircraft was proceeding direct to Trasadingen VOR. After the captain of the 154 said "Look here, it indicates zero", and more than a minute before the collision, with the autopilot pitch channel and roll channel still engaged, the airplane turned at a bank angle of 10° to the right a total of 10° heading change. Was this using the TCAS as a lateral conflict avoidance tool? Would they have missed each other if this slight turn had not been made? Perhaps not.