TM 1-1520-240-BD CU - Copper D - Damage distance between sites DA - Department of the Army DEG - Degrees DIA - Diameter DIR - Direction DIST - Distance DMM - Digital Multimeter EA - Each EMI - Electromagnetic interference EQUIV - Equivalent F - Fahrenheit FE - Iron FOD - Foreign object damage FS. - Fuselage station Fwd - Forward HEI - High explosive incendiary HRS - Hours HT - Heat in. - inches IR - Infrared KTS - Knots L.H. Left hand LRU - Line replaceable unit Min - Minimum MOS - Military occupational specialty MP (zone) - Main rotor pylon MWO - Modification work order NAS - National aircraft standard NBC - Nuclear, biological, and chemical NO - Number Nz - Vertical load factor PY (zone) - Pylon QCA - Quick change assembly REF - Reference Req'd - Required R.H. - Right hand SD - Stiffener depth SL - Stiffener length ST (zone) - Stabilator STA - Station TB - Technical bulletin TC (zone) - Tailcone TDR - Time domain reflectometer TM - Technical manual VAC - Variable alternating current VDC - Variable direct current WL - Damage width W.L - Water line WT - Weight Glossary-4