During those very busy 1970s, the adaptive response of 2 + 1, or the 10-30 with 2 + 2, was used to try and keep more companies available for other fire duty.
It would help in stripping large areas of the city of fire protection where building fires were most heavy.
As I remember, there was an article that came out in WNYF Magazine that basically said, "for most building fires, 2 engines and 2 trucks could handle the majority of those calls". When the third engine was actually requested on the 10-75, it was more of the manpower that was needed rather than the actual piece of fire apparatus itself.
Many of the FDNY members, from Chief Officers to Firefighters, were against this policy because it put an additional huge strain on some of the already ready over worked, busiest companies throughout the city. They felt (and rightfully so), with the huge amount of fire activity going on, more fire companies were needed.
There were also many sections of the city that had added "Second Sections" to several of the busiest fire companies.
But "still", it just wasn't enough.
Priorities were also put into effect.
For reported "occupied" building fires, with numerous calls - they got the highest priority response of 3 + 2, plus a chief.
Then came reports of "vacant" building fires with a 2 + 2 response.
Outside rubbish, car fires, etc got the next highest priorities.
There were times that I remember seeing a car fire, or large rubbish fire in a vacant lot, and nobody came. The companies were just too busy and the dispatchers had nobody to send.
When we read about those so called; "FDNY War Years", there's sure a lot of truth in what those years were called.
For parts of NYC, it really was a war., with fires burning all the time.