....if the day was warm or a bit bumpy...
.. surely these tests are being done in a structured manner ... calibration-checked gauges, basic power available checks, if necessary rigging checks .... ideally around dawn, nil inversions, nil turbulence, nil wind, reduced to standard conditions, etc., etc..... ?
.. otherwise, why bother wasting one's time to get Mickey Mouse data ... ?
Yes the tests are carried out to a laid down structure, but even with the best will in the world a light aircraft will not always reach the figures on a hot day or bumpy day.......... I know it may sound strange, but it does happen and often an airtest has to be carried out on pilot availabilty when the weather and conditions are not conducive to optimum climb rates.... that is why I said if it was warm or bumpy try again.....
I did one aircraft on the UK reg that has NO climb figures published by the manufactures believe it or not........ In the end the caa read the previous figures out to me over the phone and we went by them as a guideline.
As for the mickey mouse data......... well bar those on annex 2 that is now irrelevent as there is no longer a requirement to carry out Airtests on EASA aircraft every 3 years or indeed at all, unless you have specific doubts or concerns, as is the norm with the FAA in the USA....... that is in my opinion a BAD move....... I would rather know that the twin etc etc we have just air tested will maintain height on one, even if it won't climb but just maintain it... rather than find out when it's needed that the engine you are now running on will just take you to the crash site....
I would check the prop though, but the engineer dealing with it will know its age, history etc, more than me, LAMS in its latest format has that the Prop must be overhauled IAW the manufactures recommendations.... something that not everyone may be aware of as in the past a fixed pitch item was generally on condition, whilst a wobbly item was on calender/ hours.