Narrative:

Departure ord runway 32L tower gave us a turn to 090 degree on takeoff. Established on 090 degrees climbing through 2800 ft MSL got TA noted traffic was 12 O'clock minus 100 ft less than 1/2 mi. Immediately increased rate of climb. Received RA and climbed directly over traffic at plus 300 ft. Approach was not aware of traffic approximate location was 3 mi on the 060 degree radial of ord VOR. Callback conversation with reporter revealed the following information: the flight crew was flying a B727-200 on a SID that requires the aircraft to climb so steeply that the B727 has a high deck angle. This high deck angle makes it difficult to see over the nose. The first officer said that when they got the 'TA' he shifted forward in his seat and strained to see over the nose of the aircraft. In this position he saw a low-winged, single engine 'piper type' of aircraft at less than a mi at 12 O'clock at about the same time the 'RA' came. This aircraft was less than 100 ft below them. The first officer called the traffic and said 'pull.' the captain pitched up and the first officer estimates that the miss was less than 300 ft vertical and '0' ft horizontal. The reporter said that when the departure controller was questioned about the traffic he would not answer initially, but finally said that it was 'pop up traffic with no altitude readout descending to 2500 ft.'

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Original NASA ASRS Text

Title: NMAC -- ACR HAS AN NMAC WITH A LIGHT ACFT CLASSIFIED AS 'POP-UP' TFC DURING A SID OUT OF ORD.

Narrative: DEP ORD RWY 32L TWR GAVE US A TURN TO 090 DEG ON TKOF. ESTABLISHED ON 090 DEGS CLBING THROUGH 2800 FT MSL GOT TA NOTED TFC WAS 12 O'CLOCK MINUS 100 FT LESS THAN 1/2 MI. IMMEDIATELY INCREASED RATE OF CLB. RECEIVED RA AND CLBED DIRECTLY OVER TFC AT PLUS 300 FT. APCH WAS NOT AWARE OF TFC APPROXIMATE LOCATION WAS 3 MI ON THE 060 DEG RADIAL OF ORD VOR. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE FLC WAS FLYING A B727-200 ON A SID THAT REQUIRES THE ACFT TO CLB SO STEEPLY THAT THE B727 HAS A HIGH DECK ANGLE. THIS HIGH DECK ANGLE MAKES IT DIFFICULT TO SEE OVER THE NOSE. THE FO SAID THAT WHEN THEY GOT THE 'TA' HE SHIFTED FORWARD IN HIS SEAT AND STRAINED TO SEE OVER THE NOSE OF THE ACFT. IN THIS POS HE SAW A LOW-WINGED, SINGLE ENG 'PIPER TYPE' OF ACFT AT LESS THAN A MI AT 12 O'CLOCK AT ABOUT THE SAME TIME THE 'RA' CAME. THIS ACFT WAS LESS THAN 100 FT BELOW THEM. THE FO CALLED THE TFC AND SAID 'PULL.' THE CAPT PITCHED UP AND THE FO ESTIMATES THAT THE MISS WAS LESS THAN 300 FT VERT AND '0' FT HORIZ. THE RPTR SAID THAT WHEN THE DEP CTLR WAS QUESTIONED ABOUT THE TFC HE WOULD NOT ANSWER INITIALLY, BUT FINALLY SAID THAT IT WAS 'POP UP TFC WITH NO ALT READOUT DSNDING TO 2500 FT.'

Data retrieved from NASA's ASRS site as of July 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.