Date: 201310
Local time of day: 0001-0600
Location: PIT.TRACON, PA
Aircraft: Hawker Horizon (Raytheon)
Operator: Air Taxi
Operating under: Part 135
Flight plan: IFR
Flight phase: Climb
Airspace: Class B PIT
ATC / advisory: TRACON PIT
Second aircraft: A320
Reporter organization: Government
Reporter function: Departure
Reporter qualification: Air Traffic Control Fully Certified
Second reporter function: Captain; Pilot Not Flying
Anomaly: ATC Issue All Types; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Detector: Automation Aircraft RA; Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Air Traffic Control Issued Advisory / Alert; Flight Crew Returned To Clearance; Flight Crew Took Evasive Action
Contributing factors: Human Factors; Procedure
Primary problem: Human Factors

Narrative: I was working Departure South when AGC Tower called for a release on a HS125; I issued a 030 heading and released (we normally issue a 070 for aircraft off AGC for TON VOR) but due to traffic inbound from the north for AGC the 030 heading was issued. AGC Tower has a tendency to take a long time to actually release the airplanes. An A320 was still outside our airspace to the southeast when I did this. When the pilot of the HS125 checked in I did not hear him say he was climbing to five thousand and I turned him right to get him on course and called traffic just east of AGC airport northwest bound descending to four thousand. Yes; I did miss the altitude; but if he would have been released in a timely manner it may not have been an issue. AGC Tower has to do a better job on releases.


Second narrative: The First Officer was the flying pilot and also received the IFR clearance from AGC Ground Control. The clearance was the Allegheny 5 Departure 5;000 FT as filled. After the passengers arrived; I joined the First Officer in the cockpit and discussed our clearance. We noted that the AGC 5 called for an initial altitude of 3;000 FT but we were instructed to maintain 5;000 FT.The AGC Tower cleared us for takeoff from Runway 28 with a right turn to a heading of 030. After takeoff we contacted Departure and I announced that we were climbing through 2;500 up to 5;000 FT in a turn to 030. The Controller acknowledged and told us to expect traffic at about our 10 o'clock position. Shortly thereafter; we received an RA and the First Officer descended as instructed. At about the same time; ATC told us that we should have been at 3;000 and asked who issued our clearance to 5;000 and I told them AGC Ground and also that we were descending to 3;000. ATC responded with a clearance to climb to 11;000 and a local number for Pittsburgh ATC.After landing; I called and the ATC Manager told me that the tape indicated that the Ground Controller told the First Officer that it was the AGC 5 [and] 3;000 but the First Officer read back 5;000; and after confirming the correct transponder code was told that his read back was correct. Additionally; he acknowledged that on our initial call to Departure; I announced leaving 2;500 for 5;000 and we were not instructed to stop our climb at 3;000. Both the First Officer and I thought that our initial altitude was 5;000. In the future; I will always verify any altitude that is in doubt.


Synopsis: A PIT Departure Controller and the two HS125 pilots involved describe a TCAS RA event that begins when the initial clearance altitude is misheard and not corrected on read back. On initial contact with the Departure Controller the incorrect assigned altitude is stated and again not corrected and the RA ensues.