I went out to check as I heard this as well in Newmachar...... I'm almost certain it was an orbiting Nimrod flying from the North of the city out over the sea then turning back to the South of the city and heading North again before repeating. It flew over head my house every 7 or 8 minutes. I saw / heard it four times before it disappeared. The nav lights and beacon were clearly visible but it was difficult to make out the type. However given the fruity grunt almost defintely a Nimrod. The smoky trail would have been a give away if it wasn't dark!
