Non tower airport unicom -- the reporter witnesses a pattern deviation at a non tower airport.

Attributes
ACN	298161
Time
Date	199503
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : n51
State Reference	NJ
Altitude	msl bound lower : 1200 msl bound upper : 1200
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	descent : approach landing other other
Flight Plan	None
Aircraft 2
Make Model Name	Cessna Aircraft Undifferentiated or Other Model
Operating Under FAR Part	other : unknown
Flight Phase	other
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private pilot : instrument
Experience	flight time last 90 days : 20 flight time total : 1200 flight time type : 15
ASRS Report	298161
Person 2
Affiliation	Other
Function	other personnel
Qualification	other other : other
Events
Anomaly	non adherence : published procedure other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I was doing air work north of solberg airport, listening on solberg -- common TA frequency, called entry to left downwind runway 4 on 45 degree, behind a cessna, at traffic pattern altitude of 1200 ft. On entry, I noticed a second cessna approaching the downwind above traffic pattern altitude about 1 1/2 mi upwind of midfield, seemingly almost directly over the runway -- I assumed the cessna was overflying solberg. While watching it and continuing my downwind I noticed it gradually descending to about 500 ft, paralleling the downwind about 1/8 mi from the runway -- it passed well below me and between the cessna ahead of me just turning final and me. It continued its path away from the airport. I had slowed to 80 KIAS on downwind in anticipation of a conflict -- it continued flying to about 1 mi southwest of the airport as I turned base descending. Much to my surprise, the errant cessna called 'left base behind the plane ahead.' I landed and no conflict occurred. It stresses the need for constant vigilance in the pattern -- not everyone uses a radio or calls out all legs of their pattern, and not everyone flies the same types of patterns.

Original NASA ASRS Text

Title: NON TWR ARPT UNICOM -- THE RPTR WITNESSES A PATTERN DEV AT A NON TWR ARPT.

Narrative: I WAS DOING AIR WORK N OF SOLBERG ARPT, LISTENING ON SOLBERG -- COMMON TA FREQ, CALLED ENTRY TO L DOWNWIND RWY 4 ON 45 DEG, BEHIND A CESSNA, AT TFC PATTERN ALT OF 1200 FT. ON ENTRY, I NOTICED A SECOND CESSNA APCHING THE DOWNWIND ABOVE TFC PATTERN ALT ABOUT 1 1/2 MI UPWIND OF MIDFIELD, SEEMINGLY ALMOST DIRECTLY OVER THE RWY -- I ASSUMED THE CESSNA WAS OVERFLYING SOLBERG. WHILE WATCHING IT AND CONTINUING MY DOWNWIND I NOTICED IT GRADUALLY DSNDING TO ABOUT 500 FT, PARALLELING THE DOWNWIND ABOUT 1/8 MI FROM THE RWY -- IT PASSED WELL BELOW ME AND BTWN THE CESSNA AHEAD OF ME JUST TURNING FINAL AND ME. IT CONTINUED ITS PATH AWAY FROM THE ARPT. I HAD SLOWED TO 80 KIAS ON DOWNWIND IN ANTICIPATION OF A CONFLICT -- IT CONTINUED FLYING TO ABOUT 1 MI SW OF THE ARPT AS I TURNED BASE DSNDING. MUCH TO MY SURPRISE, THE ERRANT CESSNA CALLED 'L BASE BEHIND THE PLANE AHEAD.' I LANDED AND NO CONFLICT OCCURRED. IT STRESSES THE NEED FOR CONSTANT VIGILANCE IN THE PATTERN -- NOT EVERYONE USES A RADIO OR CALLS OUT ALL LEGS OF THEIR PATTERN, AND NOT EVERYONE FLIES THE SAME TYPES OF PATTERNS.

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.