Serial number 27 21745. Deciphering the coding from Armstrong's serial number list, the "27" + "50" equals 1977 production. No bent, broken or sluggish keys, no broken springs. So that the problem can be resolved.

Brand: Armstrong
Type: Concert Flute
Body Material: Brass
Exact Year: 1977
MPN: 104
Country/Region of Manufacture: United States
Machine Head Material: Silver Plated
Headjoint Material: Silver Plated
Riser Material: Silver Plated