Photos in the CNET's Up close with the first Boeing 787-9 include the one below with the caption

Boeing 787-9 at Farnborough The back of the first 787-9 has coiled tubing extended from the back of the plane's tail during test flights. It's used to measure the true air pressure to compare with the different higher and lower pressures near the plane.

Apparently this is from 2014.

Question: What is this kind of tube called, how is it used, what structure is at the far end of the tube when deployed, and why does it need to be so long?

Boeing 787-9 at Farnborough tube to measure air pressure

Published:July 13, 2014 Caption:Stephen Shankland Photo:Stephen Shankland/CNET


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