Narrative:

While in cruise at 4000' headed southbound on V29 approximately 10 NM north of the ptw VOR, phl approach issued a traffic alert to us. Traffic was reported as unconfirmed at our 12 O'clock position, less than a mile circling at 3900'. Along with the traffic report an immediate right turn to 270 degrees was issued and the captain (PF) immediately entered a 45 degree bank to the right. Neither the captain nor the first officer saw the aircraft. About 2 mins later the unconfirmed aircraft called phl approach for traffic advisories as he was an aircraft with sky divers in a climbing spiral. His actual altitude at the time of our traffic alert was unconfirmed. Contributing factors and corrective actions: since the start of the new east coast plan, ATC has required us to be at 3000-4000' on V29 between allentown and philadelphia. This unusually low altitude for a turbine aircraft which cruises at 245 KTS has created a dangerous problem by mixing a fast commuter aircraft with slower GA that fly out of the numerous airports between allentown, pottstown and philadelphia. The pilots and our company management has requested ATC for higher altitudes along this route west/O any alleviation of the problem.

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Original NASA ASRS Text

Title: SMT GIVEN SAFETY ALERT ON UNK TRAFFIC BY APCH CTLR, SMT GIVEN TURN, TRAFFIC NEVER SIGHTED BY SMT.

Narrative: WHILE IN CRUISE AT 4000' HEADED SBND ON V29 APPROX 10 NM N OF THE PTW VOR, PHL APCH ISSUED A TFC ALERT TO US. TFC WAS RPTED AS UNCONFIRMED AT OUR 12 O'CLOCK POS, LESS THAN A MILE CIRCLING AT 3900'. ALONG WITH THE TFC RPT AN IMMEDIATE RIGHT TURN TO 270 DEGS WAS ISSUED AND THE CAPT (PF) IMMEDIATELY ENTERED A 45 DEG BANK TO THE RIGHT. NEITHER THE CAPT NOR THE F/O SAW THE ACFT. ABOUT 2 MINS LATER THE UNCONFIRMED ACFT CALLED PHL APCH FOR TFC ADVISORIES AS HE WAS AN ACFT WITH SKY DIVERS IN A CLBING SPIRAL. HIS ACTUAL ALT AT THE TIME OF OUR TFC ALERT WAS UNCONFIRMED. CONTRIBUTING FACTORS AND CORRECTIVE ACTIONS: SINCE THE START OF THE NEW EAST COAST PLAN, ATC HAS REQUIRED US TO BE AT 3000-4000' ON V29 BTWN ALLENTOWN AND PHILADELPHIA. THIS UNUSUALLY LOW ALT FOR A TURBINE ACFT WHICH CRUISES AT 245 KTS HAS CREATED A DANGEROUS PROB BY MIXING A FAST COMMUTER ACFT WITH SLOWER GA THAT FLY OUT OF THE NUMEROUS ARPTS BTWN ALLENTOWN, POTTSTOWN AND PHILADELPHIA. THE PLTS AND OUR COMPANY MGMNT HAS REQUESTED ATC FOR HIGHER ALTS ALONG THIS ROUTE W/O ANY ALLEVIATION OF THE PROB.

Data retrieved from NASA's ASRS site as of August 2007 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.