Last few on Local Crossword

[boxtops]

Help, please:

1a The sort of valve to take the pressure off (6) ??F???

1d Seize a bit of air (6) ??A?C?

3d Temporarily secures a levy, we hear (5) ??C?S (could this be Docks?)

first letter of the 1s if obviously the same
5th letter of 1a is the first letter of 3d

Many thanks!

[scotman]

1A safety
3D tacks

[scotman]

1D snatch

[boxtops]

Thanks scotman, that's me all done - can you explain Snatch, please? (I understand it as seize, and a weightlifting term?)

[sandyRoe]

snatch is also a tune

[scotman]

snatch is a fragment of a song(air)

[boxtops]

Thank you both, I understand! All done, thank you.