| Drivez,
Without having been present to see what you saw, it's hard to comment on the particulars that the two aircraft may have seen or used. I've flown in and our of Deer Valley many occasions, usually in turbojet or turboprop equipment. The airport has, as you saw, a fairly high traffic density, largely with student pilot training. I can tell you from a much faster airplane's perspective, entering the traffic pattern there with so many students practicing and taking training can be not only frustrating but on occasion even a little uncomfortable...as students don't always elect to do what they should, cut others off, etc. I've had it happen there a few times.
In a training environment, why an instructor might choose to have the pilot retard power and pitch down or up would really depend on the point being made and what was going on at the time.
It's not normal for one aircraft to power back and pitch down, and another to power back and pitch up when meeting...but then it's not normal to meet, either. From the ground, parallax tends to distort the way airplanes appear to come together as they approach or fly together; this can be particularly true on a parallel approach. Especially so if one aircraft is flying a steeper approach than the other, and/or one is faster than the other.
With a smaller training field such as Deer Valley, using runways that are relatively close together, one runway will use a right hand traffic pattern while the other uses a left...this puts aircraft coming toward each other and converging as they turn the base leg for landing. Additionally, where the ends of the runways are not together, or an aircraft is landing long, the descent paths can create an illousion that might appear that the airplanes are diving through each other's approach path. As the aircraft approach on base and then turn toward the runway, it's easy to imagine how an airplane that's fast and low might reduce power and pitch up, and an aircraft that's high might reduce power and pitch down. Again, the specifics of what happened are only known to you and the pilots whom you witnessed.
Certainly midair collisions do occur. Not long ago a well publicized one occured in Phoenix between two news helicopters. Another occured a few years ago over the Scottsdale airport. I very nearly had one myself a few years ago on more than one occasion over Scottsdale, where a mix of no radar control, very diverse operations between high speed turbojets and small piston airpalnes and helicopters, and a busy demand on a single runway can create a potentially tense situation.
On one occasion I departed in the morning into the sun, after holding on the runway while a confused private pilot in a cherokee was told to turn a midfield crosswind (fly away from the runway). He reported doing so, I was cleared to takeoff, and as I climbed rapidly off the end of the runway in a Learjet, I passed very close to the Cherokee....who wasn't at all where he said he was, and who was hidden in the morning sun.
Over the past years, I've had very close encounters with other aircraft, on several occasions close enough to see what brand of sunglasses the other pilot was wearing. In most cases it's been in radar contact, talking to a controller, and in a few cases in situations in which I "owned" the special use airspace. Even with all the precautions and all the aircraft participating, mid air collisions do continue to occur. I can't say if you saw one nearly happen or not, but it's not unreasonable to imagine that you could have. With that said, considering the number of successful aircraft operations that take place on a daily basis, the midair collision still remains a very rare occurence...and many things we see from the ground that look like close calls aren't really that close in the air. |