Inquiries are continuing into an incident where a Flybe flight from Sumburgh to Inverness was diverted to Wick last Thursday.
The aircraft, with 13 passengers and three crewmembers on board, made an emergency landing after smoke appeared in the cabin and cockpit.
Flight number 6910 was on the second leg of its journey between Kirkwall and Inverness when crew noticed the smoke shortly after 9am.
Emergency services were on stand-by at Wick where the Saab 340 plane landed safely. No-one was injured.
A spokesman for operator Loganair said: “The pilots carried out emergency drills including shutting down the aircraft’s right-hand engine, which was identified as the source of the smoke. The aircraft was diverted to Wick where 13 passengers disembarked safely.
“The emergency services attended the scene, as is routine in these circumstances. Loganair takes the safety of its passengers and crew very seriously and is presently carrying out a full inspection of the aircraft to determine the cause of the incident.
“An aircraft was dispatched from Aberdeen Airport to Wick to enable passengers to continue their journey on to Inverness, where they arrived approximately two hours behind schedule.”
The spokesman said it was too early to say what had caused the problem, although he confirmed it was a “mechanical default”. The plane was grounded in Wick on Friday where a Loganair maintenance crew replaced the right engine in its entirety.