Close proximity two GA small aircraft aircraft entering traffic pattern at ttn.

Attributes
ACN	135100
Time
Date	199001
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : ttn
State Reference	NJ
Altitude	msl bound lower : 1200 msl bound upper : 1200
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : ttn tracon : dtw
Operator	general aviation : personal
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Retractable Gear
Flight Phase	cruise other other
Route In Use	approach : visual
Flight Plan	None
Aircraft 2
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other other
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Experience	flight time last 90 days : 12 flight time total : 1126 flight time type : 275
ASRS Report	135100
Person 2
Affiliation	Other
Function	flight crew : single pilot
Events
Anomaly	conflict : nmac
Independent Detector	other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 100 vertical : 0
Supplementary
Primary Problem	Flight Crew Human Performance

Narrative:

Departed lancaster, PA for destination trenton, nj (ttn) mercer co airport. Headed due east after passing willow grove NAS at 3500' MSL began descent. I called trenton tower at 12 mi (LORAN) declared 'inbound 12 mi west with ATIS.' tower advised 'fly left downwind 34.' upon my arrival at the delaware river which is 1 1/2 to 2 mi from airport I gave a position report 'crossing the river'. Tower advised 'not in sight report mid field.' I was entering left downwind on a 45 degree angle and waiting for congestion on frequency to clear so I could report position mid field when my passenger yelled 'look out.' I saw an small aircraft Y type aircraft sharply banking away from me. At this split second evasive action by me not necessary. Small aircraft Y pilot then strongly informed tower there was an small aircraft X next to him. Tower asked my position and I advised 'I was maintaining a safe interval behind small aircraft Y.' he cleared me to follow small aircraft Y in to land. I called 12 mi from the field, plenty of time for me to be advised of conflicting traffic. Small aircraft X approached me from my right side and should have seen me sooner. Tower uses some sort of traffic pattern radar. Why did this not preclude the near event? If it had not been for my passenger, I would have banked to right to parallel myself downwind with runway and probably contacted left of other aircraft.

Original NASA ASRS Text

Title: CLOSE PROX TWO GA SMA ACFT ENTERING TRAFFIC PATTERN AT TTN.

Narrative: DEPARTED LANCASTER, PA FOR DEST TRENTON, NJ (TTN) MERCER CO ARPT. HEADED DUE E AFTER PASSING WILLOW GROVE NAS AT 3500' MSL BEGAN DSCNT. I CALLED TRENTON TWR AT 12 MI (LORAN) DECLARED 'INBND 12 MI W WITH ATIS.' TWR ADVISED 'FLY LEFT DOWNWIND 34.' UPON MY ARR AT THE DELAWARE RIVER WHICH IS 1 1/2 TO 2 MI FROM ARPT I GAVE A POSITION REPORT 'XING THE RIVER'. TWR ADVISED 'NOT IN SIGHT REPORT MID FIELD.' I WAS ENTERING LEFT DOWNWIND ON A 45 DEG ANGLE AND WAITING FOR CONGESTION ON FREQ TO CLEAR SO I COULD REPORT POSITION MID FIELD WHEN MY PAX YELLED 'LOOK OUT.' I SAW AN SMA Y TYPE ACFT SHARPLY BANKING AWAY FROM ME. AT THIS SPLIT SECOND EVASIVE ACTION BY ME NOT NECESSARY. SMA Y PLT THEN STRONGLY INFORMED TWR THERE WAS AN SMA X NEXT TO HIM. TWR ASKED MY POSITION AND I ADVISED 'I WAS MAINTAINING A SAFE INTERVAL BEHIND SMA Y.' HE CLRED ME TO FOLLOW SMA Y IN TO LAND. I CALLED 12 MI FROM THE FIELD, PLENTY OF TIME FOR ME TO BE ADVISED OF CONFLICTING TFC. SMA X APCHED ME FROM MY RIGHT SIDE AND SHOULD HAVE SEEN ME SOONER. TWR USES SOME SORT OF TFC PATTERN RADAR. WHY DID THIS NOT PRECLUDE THE NEAR EVENT? IF IT HAD NOT BEEN FOR MY PAX, I WOULD HAVE BANKED TO RIGHT TO PARALLEL MYSELF DOWNWIND WITH RWY AND PROBABLY CONTACTED LEFT OF OTHER ACFT.

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.