Originally Posted by
XtremeF150
The DC9-50 had a blocking plate with a safety wire to stop flaps 50 unless an emergency. I think that was related to the hush kits.
The 727 had the same thing. Flaps 40 was blocked. All the 727 and DC9 aircraft had that type of arrangement. They could not meet the noise standards with just hushkits.
The 727 would really come down with flaps 40.