Atx pilot under lax TCA 11 mi from VOR had police helicopter make a pass.

Attributes
ACN	157296
Time
Date	199009
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : lax
State Reference	CA
Altitude	msl bound lower : 1900 msl bound upper : 1900
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : lax
Operator	common carrier : air taxi
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other
Flight Plan	None
Aircraft 2
Operator	other
Make Model Name	Helicopter
Flight Phase	cruise other
Flight Plan	None
Person 1
Affiliation	company : air taxi
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : commercial pilot : atp
Experience	flight time last 90 days : 200 flight time total : 1700 flight time type : 250
ASRS Report	157296
Person 2
Affiliation	government other
Function	flight crew : single pilot
Qualification	other other : other
Events
Anomaly	conflict : airborne less severe other anomaly other other anomaly other
Independent Detector	other other : unspecified cockpit
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	other

Narrative:

Was flying from fullerton to van nuys under the TCA. By direct route. Using dms to maintain distance from lax. I didn't go closer than 11 DME but it occurred to me that using a VFR chart there is no indication of where the 10 NM segment is measured from. I used the lax VOR and later on the ground using a plotter confirmed it as correct. But what about less experienced pilots. It could be from center of airport or from ILS/DME. In any case if it was marked as such on the chart one could breath easier.what brought it to my attention navigating by the TCA chart and using as a back up was that a sheriffs helicopter changed course and flew directly at me climbing in what I can call an attempt to read my 'north' number. I'm positive that I didn't bust the TCA but found no way to explain the actions of the helicopter. Please review this and perhaps we can make flying around the TCA a little easier. Because as it stands VFR inside the TCA is disallowed unless using corridors or landing at lax.

Original NASA ASRS Text

Title: ATX PLT UNDER LAX TCA 11 MI FROM VOR HAD POLICE HELICOPTER MAKE A PASS.

Narrative: WAS FLYING FROM FULLERTON TO VAN NUYS UNDER THE TCA. BY DIRECT RTE. USING DMS TO MAINTAIN DISTANCE FROM LAX. I DIDN'T GO CLOSER THAN 11 DME BUT IT OCCURRED TO ME THAT USING A VFR CHART THERE IS NO INDICATION OF WHERE THE 10 NM SEGMENT IS MEASURED FROM. I USED THE LAX VOR AND LATER ON THE GND USING A PLOTTER CONFIRMED IT AS CORRECT. BUT WHAT ABOUT LESS EXPERIENCED PLTS. IT COULD BE FROM CTR OF ARPT OR FROM ILS/DME. IN ANY CASE IF IT WAS MARKED AS SUCH ON THE CHART ONE COULD BREATH EASIER.WHAT BROUGHT IT TO MY ATTN NAVIGATING BY THE TCA CHART AND USING AS A BACK UP WAS THAT A SHERIFFS HELI CHANGED COURSE AND FLEW DIRECTLY AT ME CLBING IN WHAT I CAN CALL AN ATTEMPT TO READ MY 'N' NUMBER. I'M POSITIVE THAT I DIDN'T BUST THE TCA BUT FOUND NO WAY TO EXPLAIN THE ACTIONS OF THE HELI. PLEASE REVIEW THIS AND PERHAPS WE CAN MAKE FLYING AROUND THE TCA A LITTLE EASIER. BECAUSE AS IT STANDS VFR INSIDE THE TCA IS DISALLOWED UNLESS USING CORRIDORS OR LNDG AT LAX.

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.