British Airways Boeing 777-236ER G-VIIB operating BA109 London Heathrow – Dubai (depart London Heathrow 1st April) diverted via Muscat this morning due to long hold times at Dubai caused by a sandstorm. This caused a delay to the return BA108, the crew of which signed in on time at Dubai and consequently did not have sufficient hours to reach London Heathrow once the flight departed. The aircraft therefore diverted via Vienna where a new crew had positioned in order to take over.