Here is the full list of all 14 Dustoff Heli Rescue achievements.
Complete the last mission with the M60 gun
Save Rambo
Earn golden medal on every mission
Earn at least silver medal on every mission
Complete every mission
Save 200 soldiers
Save 100 soldiers
Find Buddha
Save 50 soldiers
Survive hitting a tree
Pick up 20 soldiers without landing
Die within the first 4 seconds.
Spin with the Scout twice at the same time
Spin with a full Scout