Narrative:

ATC cleared us for departure, heading 360 degrees to maintain 3000 ft. Communication on CTAF revealed only 1 conflict, a touch-and-go to remain in pattern on short final runway 25. Following departure, turned right to 360 degrees and began climb at approximately 2000 FPM. Nearly immediate TCASII alert head-on with target at same altitude. Second alert sounded (aerostar) as descending aircraft entered pattern (right traffic downwind, runway 25). Reaching 3000 ft (clearance limit) had choice of striking first aircraft (slow moving single), descending forward (no time) descending left (antennae farm), ascending right (joining busy pattern at high speed) or, continuing climb to avoid both aircraft (option chosen). Climbed to approximately 4200 ft, told ATC my predicament, descended, was given 6000 ft. Altimeter showed 6000 ft when ATC showed 6800 ft. Cycled air source and cycled pitot heat and confirmed breaker set. Then, altitude showed 5800 ft, when ATC showed 6000 ft. Suspect frozen pitot (2 inch snow fall, slush on runway during previous night's landing). ATC never reported opposite direction arrs for downwind right traffic runway 25. Lucky to have missed both aircraft, but ATC complained of altitude deviation. Recommend review of ATC practices regarding this airport.

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Original NASA ASRS Text

Title: A CITATION 500 PLT, DEPARTING FROM LPR, AN UNCTLED FIELD, ON AN IFR CLRNC, EXPERIENCED 2 NMACS AND TOOK EVASIVE ACTION TO AVOID COLLISION, CAUSING HIM TO OVERSHOOT HIS ASSIGNED ALT.

Narrative: ATC CLRED US FOR DEP, HDG 360 DEGS TO MAINTAIN 3000 FT. COM ON CTAF REVEALED ONLY 1 CONFLICT, A TOUCH-AND-GO TO REMAIN IN PATTERN ON SHORT FINAL RWY 25. FOLLOWING DEP, TURNED R TO 360 DEGS AND BEGAN CLB AT APPROX 2000 FPM. NEARLY IMMEDIATE TCASII ALERT HEAD-ON WITH TARGET AT SAME ALT. SECOND ALERT SOUNDED (AEROSTAR) AS DSNDING ACFT ENTERED PATTERN (R TFC DOWNWIND, RWY 25). REACHING 3000 FT (CLRNC LIMIT) HAD CHOICE OF STRIKING FIRST ACFT (SLOW MOVING SINGLE), DSNDING FORWARD (NO TIME) DSNDING L (ANTENNAE FARM), ASCENDING R (JOINING BUSY PATTERN AT HIGH SPD) OR, CONTINUING CLB TO AVOID BOTH ACFT (OPTION CHOSEN). CLBED TO APPROX 4200 FT, TOLD ATC MY PREDICAMENT, DSNDED, WAS GIVEN 6000 FT. ALTIMETER SHOWED 6000 FT WHEN ATC SHOWED 6800 FT. CYCLED AIR SOURCE AND CYCLED PITOT HEAT AND CONFIRMED BREAKER SET. THEN, ALT SHOWED 5800 FT, WHEN ATC SHOWED 6000 FT. SUSPECT FROZEN PITOT (2 INCH SNOW FALL, SLUSH ON RWY DURING PREVIOUS NIGHT'S LNDG). ATC NEVER RPTED OPPOSITE DIRECTION ARRS FOR DOWNWIND R TFC RWY 25. LUCKY TO HAVE MISSED BOTH ACFT, BUT ATC COMPLAINED OF ALTDEV. RECOMMEND REVIEW OF ATC PRACTICES REGARDING THIS ARPT.

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.