Expert: Paul Soderman - 7/22/2009

Question
I am in France and as we were driving down a road we come across a house with a ryanair airplane hovering on top, it was about 10 feet above the house. I didn't think it was possible but as we stopped to take a closer look it had actually stopped in midair. It was very windy and I am wondering that maybe the plane had been caught in cross winds and couldn't move. Please can you explain this?

Answer
Hi Abby
There are a couple mysteries here.  My understanding is that Ryanair flies the Boeing 737-800 aircraft.  This is a fairly large jet that should not be 10 ft over any house.  And its stall speed is roughly 250 km/h (150 mph), which is faster than any wind except a hurricane.  Theoretically, an aircraft whose airspeed is equal to the speed of a headwind would appear to be hovering.  But I doubt the winds were that great that day. Plus he would be flying well above stall speed. So, my inclination is to believe that you experienced an optical illusion.  The airplane may have looked like it was 10 ft above the house but was really much distant.  And a distant airplane slowing to land in a headwind could seem to be almost hovering.  Or perhaps it was turning in such a way that the apparent speed perpendicular to your line of sight was small.

Or maybe it was a model airplane designed after a Ryanair aircraft and really was 10 ft over the house flying into a headwind strong enough to allow it to hover.  Come to think of it, the updraft over a house could allow a model airplane or glider to hover just as birds can hover near cliffs and ridges.

What do you think ?
Paul