In Flight International 3-9 September you carried an article and photograph about a large helium balloon which was launched by NASA from Lynn Lake, Manitoba on 25 August, before its payload was parachuted back to Earth a day later, and "a command sent from the ground to tear the envelope".
On the late afternoon of 21 September I was flying an Airbus A320 at 35,000ft (10,700m) down airway UL611, between Pula and Split in Croatia when both the first officer and I noticed a huge balloon above us and just to the west of the airway. The balloon envelope was a silver-grey colour and enormous, but it appeared to have no gondola or payload beneath it. We estimated its altitude to be 40,000ft or perhaps higher. We reported the sighting to Zagreb air traffic control, who told us that while several other aircraft had reported the object, their radar was only picking it up intermittently.
Although the balloon was higher than most air traffic, it would have posed a serious navigational hazard if it had descended a few thousand feet (perhaps due to nocturnal cooling of the gas).
As far as I know, all the usual suspects (Fossett, Branson, etc) were earth bound that day, and frankly not many owners can have misplaced a balloon of this size without being aware of its disappearance. Is NASA certain that it successfully deflated the Lynn Lake balloon (was the envelope recovered?), or was that UL611 object their envelope "gone walkabout"?
Adrian Akers-Douglas
Captain, Eurocypria Airlines
Larnaca, Cyprus
Source: Flight International
