Date: 201402
Local time of day: 1201-1800
Location: VNY.Airport, CA
Flight conditions: IMC
Weather elements / visibility: Turbulence
Aircraft: Gulfstream IV / G350 / G450
Operator: Corporate
Operating under: Part 91
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class E SCT
ATC / advisory: TRACON SCT
Second aircraft: B737 Undifferentiated or Other Model
Reporter organization: Corporate
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Training / Qualification; Situational Awareness
Second reporter function: Captain; Pilot Not Flying
Anomaly: Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Automation Aircraft RA; Automation Aircraft TA
When detected: In-flight
Result: Flight Crew Returned To Clearance; Flight Crew Took Evasive Action
Contributing factors: Airspace Structure; Human Factors; Weather
Primary problem: Human Factors

Narrative: A deviation in altitude occurred during initial approach to Van Nuys Airport. I was hand flying the airplane due to turbulence encountered on descent. While on frequency with SoCal Approach; we were given a heading of 070 degrees. We were level at 5;000 FT in IMC conditions with continued light to occasional moderate turbulence. At approximately 4 miles from KADIE Intersection; we were given a heading of 130 degrees to intercept the localizer and clearance for the ILS for Runway 16R at VNY. While in the turn to intercept the localizer with continued turbulence; we received a TA message from our TCAS system. I initially climbed thinking that there was traffic right below us. I increased our altitude to 5;500 FT. Upon further review of the TCAS we received an RA to descend. I complied with RA advisory and descended immediately. I leveled off back to 5;000 FT and intercepted the localizer for the ILS Runway 16R at Van Nuys and landed. We notified SoCal Approach of what we had experienced. SoCal also advised us that traffic above us; a Boeing 737; had responded to an RA to climb. After the flight; my Co-Captain and I took the initiative to contact the SoCal Approach Controller by phone to describe our experience. The SoCal Approach Controller thanked us for taking the initiative to call him. He understood why I felt the urgent need to climb. He indicated to us that there was never a loss of separation and safety was not compromised.


Second narrative: A deviation in altitude occurred during initial approach into Van Nuys Airport. My Co-Captain was hand flying the airplane due to turbulence encountered on descent. While on frequency with SoCal Approach; we were given a heading of 070 degrees. We were level at 5;000 FT in IMC conditions with continued light to occasional moderate turbulence.At approximately 4 miles from KADIE Intersection; we were given a heading of 130 degrees to intercept the localizer and clearance for the ILS for Runway 16R at VNY. While in the turn to intercept the localizer with continued turbulence; we received a TA message from our TCAS system. My Co-Captain initially climbed thinking that there was traffic just below us; the altitude increased to 5;500 FT. Upon further review of the TCAS we received an RA to descend. My Co-Captain then complied with the RA advisory and descended immediately. The aircraft was leveled off back at 5;000 FT and intercepted the localizer for the ILS Runway 16R Van Nuys.We notified SoCal Approach of what we had experienced. SoCal also advised us that traffic above us; a Boeing 737; had responded to an RA to climb.


Synopsis: G-IV flight crew experiences a TCAS TA at 5;000 FT and the flying Captain climbs 500 FT thinking the traffic is below. The traffic is above and a TCAS RA is generated to descend. A normal approach and landing ensues.