12 votes
Accepted

What does this 'R' number mean on the ND of this Airbus?

That is the cross track error shown on the Navigation Display (ND): 9 Cross Track Error This is the aircraft's lateral deviation from the active leg of the flight plan (related to the great circle ...
  • 47.9k
10 votes
Accepted

What is the round tube mounted on the roof just behind the windshield of a PC-6?

The vertical tube on top of the cabin is the fuel system vent mast: Pictures are taken from an online copy of Royal Australian Air Force Pilatus Porter Flight Manual, Australian Air Publication 7211....
  • 21.9k
9 votes

What does this 'R' number mean on the ND of this Airbus?

19.1NM Right of flight plan track
  • 1,461
1 vote

What are these painted lines on the fan blades of the Rolls-Royce Pearl 15?

Expanding on the answer from user14897, these roughness strips work like the dimples on golf balls. They trip the boundary layer from laminar to turbulent, which helps keep the flow attached. A ...

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