For a DR300, I’d choose an independent inspector with experience of wooden Robin aircraft.
Give the inspector time to review the structure and repair history. Ask them to assess the wooden components, glued joints and covering using the applicable maintenance instructions, and to investigate any evidence of moisture or previous damage. Ask what could actually be inspected and whether anything needs further access.
The paperwork should explain previous structural repairs, covering work and modifications. Recent paint or fabric work is worth understanding: what was done, why was it needed, and what was inspected underneath?
The landing gear also deserves attention. EASA AD 2018-0018 covers the nose landing gear support plate on affected DR300 aircraft, including the DR300/125. Have the inspector check applicability, compliance records and the rest of the aircraft’s current AD status.
Include the engine, propeller and upcoming maintenance in the same review. A recent annual inspection is useful background, but I’d still commission a purchase inspection with an agreed scope.
The Robin DR300/125 on CollectAirs provides a starting point for questions to put to the seller.
References: EASA AD 2018-0018 and the UK CAA Airworthiness Code.
If you’ve bought or maintained a DR300, which finding would you tell a first-time buyer to pay attention to?