On Nav computer: put temperature (-44ºC) next
to Mach No. Index in the AIR SPEED window, go to Mach No. (0.86) on the inner
scale and read TAS next to it on the outer scale: 507 kts.
With a wind component of -110kts the ground speed is 397kts. Put 60 (minutes)
on the inner scale next to the groundspeed (397kts) on the outer scale, go to
420nm on the outer scale and read time it will take next to it on the inner
scale: 63.5 minutes.
To delay by 5 minutes to aircraft needs to cover 420nm in 68.5 minutes:
put 68.5 (minutes) on the inner scale next to 420 (nm) on the outer scale, go
to 60 (minutes) on the inner scale and read the required ground speed on the
outer scale: 368kts.
With a wind component of -110kts a groundspeed of 221kts will require a
TAS of 478 kts.
In the AIRSPEED window put temperature (-44ºC) next to the Mach No.
Index, got TAS 478kts on the outer scale and read Mach No. next to it on the
inner scale: 0.81