On the specific subject of t&g in a twin, I always just have to wonder what the purpose is
Generally efficiency. In the Pitts, I can do
25 approaches and landings, doing touch
and goes, in one hour. Lots of experience
there for the student. And far more challenging
than a twin, I might add.
Twins are so hideously expensive - and FTU's
don't help by charging via Hobbs instead of
tach time, which is the biggest ripoff ever - I
can understand people wanting to get good
value for their very expensive multi-engine
training dollar.
Again, a 10,000 foot runway at sea level makes
this moot. Lots of time to do stuff carefully.
Jets are even more hideously expensive than
FTU twins. Hence touch and goes in them,
too. A TC Inspector would heat up and melt
down the brakes doing full stop landings, but
no brakes are required for touch and goes.
I might add that even though I will never be
as good a pilot as a TC Inspector, I do touch
and goes in ex-military jets on a 4,000 foot
runway.
TC Inspectors don't bother reading the flight
manuals, but I do, and I have to comply with
this in one of the jets that I fly:
The maximum speed at which wheel brakes may be applied
with landing weight up to 4,600 kg {10,140 lbs) is 190 km/h
(102 kts).
In cases such as an aborted takeoff, when full
brakes are applied at speed higher than 100 km/h
(55 knots), the brakes must be allowed to cool
before a subsequent flight.
For an aircraft with an initial takeoff weight of up to
4,400 kg (9,710 lbs), 10 landings and braking is permitted,
with a minimum of 7 minutes interval between landings
For an aircraft with initial takeoff weight of more than
4,400 kg (9,710 lbs), continuous circuits with braking is allowed,
but a minimum of 30 minutes interval between landings