Mentor/Turbo Mentor (T-34)
Air Traffic Control Fully Certified
Communication Breakdown; Situational Awareness; Workload
ATC Issue All Types
Air Traffic Control Issued New Clearance
Human Factors; Procedure
[There] was a flight of three T-34s enroute to TEB. They were handed off to me near DQO; direct to MXE.V3.SJB..TEB at 9;000. I pointed out the flight to South Departure and turned [the T-34s] direct to MAZIE.V3. A short time later; [the T-34s] requested lower; so I cleared the flight to 7;000. I then pointed out the flight to North Arrival direct MAZIE at 7;000. A short time after that; when [the T-34s] were about 10 miles north of PHL; I noticed the flight off course and asked them to 'verify direct MAZIE' to which the pilot responded; 'affirmative; direct MAZIE'. The flight then requested lower again. I requested control for descent from North Arrival and pointed out the flight to Yardley. I issued 5;000 to [the T-34s]. Just after [the T-34s] began descending out of 7;000; I noticed a VFR target (1200 code) descending out of 6;800 in the BRAVO airspace heading east southeast bound; about 3 miles southeast of [the T-34s]. I asked [the T-34s] if he had 'lost a wingman'. At that time [the second T-34] called me; stating he had broken off of [the group]; was VFR; and was requesting a clearance to TEB. I initially obtained a VFR code for [the second T-34]; thinking he wanted to stay VFR to TEB in the BRAVO. At this time; [the third T-34] called and said 'I also broke off and am requesting a squawk code' or something to that effect. I noticed a primary RADAR target just south of [the first T-34's] position. I obtained an IFR code for [the third T-34] and issued it to the pilot. [The second T-34] then stated that they wanted an IFR clearance to TEB. I dropped the VFR track on [the second T-34] and obtained and issued an IFR code to [the second T-34]. While this was going on; I was attempting to inform the Yardley and North Arrival controllers of what was happening; but became so busy trying to deal with the [T-34] aircraft that I might have missed some required coordination. I did make sure that North Arrival and Yardley did not have any traffic in the area. [The second T-34] (previously the primary target) tagged up at 7;000 FT about 3 miles southeast of [the first T-34].  [The second T-34] apparently climbed back up to 7;000 on their own when breaking off from [the first T-34]; who had been previously cleared to 5;000 direct MAZIE. [The second T-34] also turned about 30 degrees right of [the first T-34's] course. At this time; [the first T-34] was on course direct MAZIE level at 5;000. [The third T-34] tagged up at 5;500 about 3 miles southeast of [the second T-34]; eastbound (well off course). I issued control instructions to keep them separated from each other; other traffic; and to get them in-trail and at the proper LOA altitude for TEB arrivals. I ensured that both [the second T-34] and [the third T-34] were cleared to TEB via SBJ direct. I verbally coordinated the change in [the first T-34] from a flight of 3 to a single ship; and made manual hand offs on [the second T-34] and [the third T-34] to N90. Luckily during this event; there was little other traffic in the area. If this had occurred at a busy time; I have no doubt that one of more of these T34s would have lost separation; or worse; with another aircraft. [The first T-34] never informed me that they needed to break up; I had to ask them what was going on as I saw the targets spreading out. One stayed IFR and climbed and turned without clearance; while not squawking any code. Another stayed on its assigned route and altitude; while the third squawked 1200 and turned and descended into the BRAVO without a clearance. In the future I would hope that the flight leader would inform the Controller that they need to break up before the aircraft scatter. Even if they had informed me of the possibility that they needed to break up; I could have been better prepared to handle the situation. I would hope that they would request a breakup before getting into clouds or other IMC conditions that would preclude formation flight. The coordination from the pilots has to be better inthe future. Additionally; one of the pilots in this flight repeatedly read back bad altitudes. During a complex situation like an unplanned flight split; the pilot needs to pay particular attention to control instructions.
PHL Controller detailed the difficult task of breaking up a flight when no prior coordination/requests were made by the flight.