DE RATED TAKE OFF
AIR NEW ZEALAND WAS THE FIRST AIRLINE TO USE DE RATED TAKE OFF IN THE Dc8-52 BACK IN 1967.
IT WAS INTRDUCED BECAUSE IT EXTENDED THE HOT SECTION LIFE OF THE POWER PLANT.
DE RATING WAS ONLY ALLOWED WHERE IT WAS ABLE, AT A BALANCED FIELD CALCULATION.
IT GOT TANGLED UP A BIT WITH PHONEY V1s AND VMCG/VMCA,VLOF WET RUNWAYS AND A MIN HEIGHT OF 35 FT AT FAR END ETC.
iT SAVED DOLLARS!!!
THE REST OF THE WORLD TOOK A LITTLE TIME TO REALIZE THAT TEAL/AIR NEW ZEALAND GOT IT RIGHT(CORRECT)