An owner usually sees the total figure for the year and not the structure behind it. An audit turns that one line into a picture you can read: what it costs to sit on the ground, what it costs to fly, and how much you are paying for things you need not pay for.
In practice a few items come round again and again: repositioning flights that planning would have avoided; fuel at spot prices instead of contract ones; handling without an agreed rate; maintenance outside a programme where the programme would pay for itself; insurance cover with no connection to where the aircraft actually flies.
Idle time is a subject of its own. If the aircraft flies little, every fixed item falls on a small number of annual flight hours and the cost per hour multiplies. Sometimes the right conclusion from an audit is not “cut the costs” but “fly more hours, or put the aircraft under management”.
An audit does not necessarily end in lower costs. Sometimes it ends with the conclusion that the budget is normal and the questions were really about expectations — that is a useful result too, and we say so plainly.
Invoices and contracts for the period, the flight hour data, the status of the maintenance programmes and the insurance policy. The more complete the source data, the more accurate the result.
Usually 2–4 weeks for a single aircraft, including the comparison with the market and the negotiating part.
No, and it would be dishonest to promise them. What is guaranteed is a clear answer on what makes up your budget and which items can be changed — the decision stays with the owner.
Describe the situation — I answer personally and to the point.