Section 2 gives two exemptions from the 100hr per 28 days or 900 hour per year limit. They are for;
private flights with a weight limit; and
Non-public transport flights where the pilot has completed less than 25 hours since medical examination.
For an instructional flight (Aerial Work), in order to exceed the 100 hour limit, one would have to be medically exammined. I doubt if any AME would pass as fit a pilot who intentionally worked such excessive hours.
So yes one can fly a 12 hour day on 8 consecutive days and then 4 hours on the 9th but one then needs a medical to complete any further flying (other than private flying) for the next 28 days.
Most organisations such as AOPA and the BMAA remind instructors of the 100hour and 900 hour limits.
Of course, the hours you spend supervising solos, providing groundschool, pre and post flight briefs, aircraft check A and documentation are not catered for in the limits so it is entirely possible to work 16 hour days but only fly 4 hours each day.
Do instructors need any further FTL?
Regards,
DFC
Further to the above,
Taking the UK weather and overall regular VFR flying season into account, perhaps instructors in the UK should press for the same system that is provided for in Canada where up to 14 hour days are permitted for certain operators during the Summer flying season because of the weather and daylight limitations of the Winter.
Regards,
DFC