'Bit , being 'behind the a/c' the a/c is not a new idea. Nowadays it's probably part of SA. Before glass cockpits and numerous DMEs , then situational awareness was more difficult , and reliance on Flt.plans , Navlogs and ETAs was needed .
My original route chk to Belfast turned into more training required when the DME part of the TACAN failed , and my SA worsened , leading to a Hot 'n High approach .
Later you could easily see if someone was behind the a/c whilst in the cruise . Older guys coming off T/props to jets had to up their speed of thought , from 4mi/min to 10mi/min .. Was not always easy for them , if in the cruise on a GLA-LHR [ <10mins ] they had All the radio aids behind the a/c . Then I knew I had to wake up and monitor more thoroughly .
DMEs on the field made life much easier in descent planning and execution . Glass cockpits are helpful in SA and replanning , but DME and 3 x table failsafe .
'Rude and 'Full have it , 'tho in 13 yrs of FI'ing , I've always asked youngsters on trial lessons [ who are interested in flying ] to recite the 3x table ...
One mum [ a teacher ] had it when she corrected her offspring 1x3 = 3 , 2x3 = 6 etc. when he reeled off 3,6,9,12, etc... '' That's a list of 3s , not the table ''
Seems teaching can just be a list , no one has pointed out the value of the table when having only 2 pieces of info the 3rd can be deduced .
The ones that get it well , I tell '' You can fly jets '' !
rgds condor.