Narrative:

We were climbing to cruise at 3500 ft; suddenly saw a airplane climbing to us from 10 o'clock down position; I immediately took over control from student; climbing right turn to avoid him. It seemed like that airplane didn't see us; he passed by and climbing left turned around; then it became that airplane was chasing my airplane tail climbing; we have to keep climbing; and hope he could see us; finally that airplane suddenly turned away from us; it seemed like he found us. We felt relief a little bit (half minute?); but suddenly I realized I already climb to 4500 ft; entered class B (floor 4000 ft); I dived down immediately. Two airplanes passed by close. It was evening time; visibility plus 10. My airplane has no TCAS. If the airplane equipped with TCAS; it would be really helpful. Hope nobody call me for breaking into class B. If airplane equipped with some kind of airspace warning system; that would be great for training flight and VFR flight.

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Original NASA ASRS Text

Title: C172 Instructor pilot reports inadvertently entering DFW Class B while trying to avoid another aircraft in close proximity.

Narrative: We were climbing to cruise at 3500 FT; suddenly saw a airplane climbing to us from 10 o'clock down position; I immediately took over control from student; climbing right turn to avoid him. It seemed like that airplane didn't see us; he passed by and climbing left turned around; then it became that airplane was chasing my airplane tail climbing; we have to keep climbing; and hope he could see us; finally that airplane suddenly turned away from us; it seemed like he found us. We felt relief a little bit (half minute?); but suddenly I realized I already climb to 4500 FT; entered Class B (floor 4000 FT); I dived down immediately. Two airplanes passed by close. It was evening time; visibility plus 10. My airplane has no TCAS. If the airplane equipped with TCAS; it would be really helpful. Hope nobody call me for breaking into class B. If airplane equipped with some kind of airspace warning system; that would be great for training flight and VFR flight.

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.