I tried DOSBox-X (dosbox-x-windows-20200502-170825-windows.zip) and the helicopter sound is there! However, while the game is playing sounds there is a slight background hum. Thanks to all.

Thank you for the technical insight, ripsaw8080. I love these old programming tricks!

I tried the settings you suggested, but the helicopter sounds are always missing. Thanks anyway!

Thank you for your answer ripsaw8080! I just tried DOSbox ECE with default settings and the sounds are missing also in this version.

Hi to all! in this post they speculate the issue is caused by inaccurate 8088 CPU emulation: https://github.com/86Box/86Box/issues/705 In this video you can hear the sounds missing: https://www.youtube.com/watch?v=krb4ave2_Mg There is any setting I can try? Many thanks.