Trees obscured controller vision of C152 on base leg. C152 side stepped to parallel runway because o...

Attributes
ACN	279883
Time
Date	199407
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : cps
State Reference	IL
Altitude	agl bound lower : 0 agl bound upper : 150
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : cps
Operator	general aviation : corporate
Make Model Name	Gulfstream II
Operating Under FAR Part	Part 91
Navigation In Use	Other
Flight Phase	climbout : takeoff
Flight Plan	IFR
Aircraft 2
Operator	general aviation : personal
Make Model Name	Cessna 152
Operating Under FAR Part	Part 91
Flight Phase	descent : approach landing other
Flight Plan	None
Person 1
Affiliation	government : faa
Function	controller : local
Qualification	controller : non radar
ASRS Report	279883
Person 2
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe conflict : ground less severe
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Miss Distance	horizontal : 1500 vertical : 150
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	other
Situations
Airport	other physical facility

Narrative:

While working local control at an airport with parallel runways, I instructed a G-2 to taxi into takeoff position and hold. I had already cleared a C152 for touch and go on that runway. The C152 disappeared behind some trees (located on pt property near the control tower). As it turned left base the C152 emerged from behind the trees turning a short final for runway 30L, very close (less than 1/4 mi) behind the G-2, which was just reaching takeoff power. I believe a very serious collision and jet blast hazard existed, and that such occurrences will continue if the trees are not removed. Callback conversation with reporter revealed the following information: reporter stated separation was never lost. The C152 was side stepped to the parallel runway. Trees obscured the approach end of runway 30L and the reporter could not see when the G2 started to roll. Airport management has cut down trees obscuring runway. Reporter admitted the trees on private property are only a problem when pilots don't fly a proper pattern like a short approach.

Original NASA ASRS Text

Title: TREES OBSCURED CTLR VISION OF C152 ON BASE LEG. C152 SIDE STEPPED TO PARALLEL RWY BECAUSE OF G2 TKOF.

Narrative: WHILE WORKING LCL CTL AT AN ARPT WITH PARALLEL RWYS, I INSTRUCTED A G-2 TO TAXI INTO TKOF POS AND HOLD. I HAD ALREADY CLRED A C152 FOR TOUCH AND GO ON THAT RWY. THE C152 DISAPPEARED BEHIND SOME TREES (LOCATED ON PT PROPERTY NEAR THE CTL TWR). AS IT TURNED L BASE THE C152 EMERGED FROM BEHIND THE TREES TURNING A SHORT FINAL FOR RWY 30L, VERY CLOSE (LESS THAN 1/4 MI) BEHIND THE G-2, WHICH WAS JUST REACHING TKOF PWR. I BELIEVE A VERY SERIOUS COLLISION AND JET BLAST HAZARD EXISTED, AND THAT SUCH OCCURRENCES WILL CONTINUE IF THE TREES ARE NOT REMOVED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED SEPARATION WAS NEVER LOST. THE C152 WAS SIDE STEPPED TO THE PARALLEL RWY. TREES OBSCURED THE APCH END OF RWY 30L AND THE RPTR COULD NOT SEE WHEN THE G2 STARTED TO ROLL. ARPT MGMNT HAS CUT DOWN TREES OBSCURING RWY. RPTR ADMITTED THE TREES ON PVT PROPERTY ARE ONLY A PROB WHEN PLTS DON'T FLY A PROPER PATTERN LIKE A SHORT APCH.

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.

Trees obscured controller vision of C152 on base leg. C152 side stepped to parallel runway because of G2 takeoff.