Narrative:

On departure; leveled off at 1;700 feet as required by the SID till 2.2 DME then continued climb to 4;000. Started turn; GPWS (ground proximity warning system) gave a terrain warning; followed by a traffic alert triggered by a helicopter in front of us down low. Second guessed our initial heading of 113 and quickly consulted chart saw a turn to 313 depicted and started the turn. ATC controller saw us turning and issued an immediate turn back to 110. Then further right to 360 to join the departure. No conflict noted by TCAS or controller just turning when he did not expect us to. After climb out to flight levels debriefed the occurrence and discovered the heading of 313 depicted on chart was for in case of loss of radio.

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Original NASA ASRS Text

Title: Medium Transport aircraft flight crew reported turning to an incorrect heading on departure from VNY airport resulting in an airborne conflict with a Helicopter.

Narrative: On departure; leveled off at 1;700 feet as required by the SID till 2.2 DME then continued climb to 4;000. Started turn; GPWS (Ground Proximity Warning System) gave a terrain warning; followed by a traffic alert triggered by a helicopter in front of us down low. Second guessed our initial heading of 113 and quickly consulted chart saw a turn to 313 depicted and started the turn. ATC controller saw us turning and issued an immediate turn back to 110. Then further right to 360 to join the departure. No conflict noted by TCAS or Controller just turning when he did not expect us to. After climb out to flight levels debriefed the occurrence and discovered the heading of 313 depicted on chart was for in case of loss of radio.

Data retrieved from NASA's ASRS site 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.