Date: 201512
Local time of day: 0601-1200
Location: VNY.Airport, CA
Flight conditions: VMC
Weather elements / visibility: 10
Light: Daylight
Aircraft: Small Aircraft; High Wing; 1 Eng; Fixed Gear
Operator: Personal
Operating under: Part 91
Flight plan: None
Mission: Personal
Flight phase: Cruise
Airspace: Class D VNY
ATC / advisory: Tower VNY
Reporter organization: Personal
Reporter function: Pilot Flying; Single Pilot
Reporter qualification: Flight Crew Private
Human factors: Situational Awareness; Training / Qualification
Anomaly: Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control
When detected: In-flight
Result: Flight Crew Returned To Departure Airport
Contributing factors: Airspace Structure
Primary problem: Airspace Structure

Narrative: I was flying around the edge of the valley outside but just west of the VNY Class D and BUR Class C (near the Santa Susana Pass) after taking off from VNY. On approach to VNY for landing I was informed that I had been in the way of the BUR ILS approach while flying around the area (which I had not realized since I was outside of the class C and D - I had continued listening on the VNY tower frequency but didn't hear anything regarding an issue so I assumed there wasn't one). By the time I was told that I had been disrupting the approach path into BUR (on contacting the VNY tower to return for landing) I was already descending to return to VNY and continued the descent and entered the VNY D as soon as possible. Since there weren't any explicit airspace issues and I am a pilot new to the airport (and still fairly new pilot in general); I didn't realize that I had been doing anything disruptive to normal air traffic operations. (On landing; since the ground frequency was not especially busy; I confirmed with the ground controller that I hadn't violated any airspace; just been accidentally disruptive; and I apologized for the annoyance and lack of knowledge.)I don't think this is necessarily a safety issue since non-IFR-rated pilots wouldn't be flying in IMC (when I assume ILS approaches are most critical). I don't know if there's much to be done to prevent similar issues in the future; but since it does disrupt normal traffic flow it could be worth trying to raise awareness of approach procedures at class C and D airports (and the fact that they do extend beyond the boundaries of the airspace) amongst student and non-IFR-rated pilots (since unsuspecting pilots can keep aircraft in the way of an approach without ever realizing the issue or actually violating any airspace - not causing a safety issue but still creating an operational challenge). I know that the IFR routes are printed on the TAC; but with all the clutter on the charts and the fact that the nature and importance of instrument procedures for scheduled air operations aren't really mentioned at all during private pilot training their importance could be easily overlooked.




Synopsis: Aircraft operating approximately 5 miles West of VNY at altitudes around 5000 feet; while clear of VNY class D and BUR class C was advised by VNY Tower they had a potentially caused a  conflict with aircraft flying the ILS/LOC Z Runway 8 BUR.