Low Level Contrails
Discussion
I was watching an airliner making its way into Heathrow this morning. It was flying at around 8,000 to 10,000 feet (the usual height when they pass over Farnborough on their inbound legs) and it was pulling a sizeable set of contrails.
I've not seen an aircraft develop such a decent contrail at such a low altitude before. The air it was passing through must have been REALLY cold.
I've not seen an aircraft develop such a decent contrail at such a low altitude before. The air it was passing through must have been REALLY cold.
el stovey said:
We've been having a PH pilots dump fuel over Eric's house competition. Looks like someone won. Which aircraft and airline was it Eric?
I've seen a fuel dump in progress before and it didn't look like this. The contrail was definitely coming from the rear of the engines rather than the wings.The aircraft was silhoutted so I couldn't make out any colour schemes. It looked like a 767.
Depending onn the air temperature, contrails usually start forming at altitudes above 20,000. During WW2, many piston engined aircraft of that era rarely ventured above 30,000 feet, but that still mean that contrails were not that unusual. During the Battle of Britain, twisted and convuluted contrails were a common sight after the many daily air battles.
American bombers, such as the B-17, B-24 and B-29 were all capable of flying at or above 30,000 feet, due to their turbocharged engines, and therefore often left quite extensive contrails. RAF night bombing was rarely conducted above 20,000 feet.
American bombers, such as the B-17, B-24 and B-29 were all capable of flying at or above 30,000 feet, due to their turbocharged engines, and therefore often left quite extensive contrails. RAF night bombing was rarely conducted above 20,000 feet.
el stovey said:
We've been having a PH pilots dump fuel over Eric's house competition. Looks like someone won. Which aircraft and airline was it Eric?
When you do a fuel dump, do you just do it anywhere or does it have to be over certain areas (Slough hopefully?)Does the fuel reach the ground?
JonnyFive said:
When you do a fuel dump, do you just do it anywhere or does it have to be over certain areas (Slough hopefully?)
Does the fuel reach the ground?
Depends on the circumstances. If possible, it is of course preferable to get over the sea or Slough, rather than over Gods back yard of North Yorkshire. It could well be, however, that you're in a rush, so it isn't possible to avoid dumping over built up areas. However, fuel dumped above 4+ thousand feet doesn't reach the ground. This does depend slightly on the aeration level of the nozzles.Does the fuel reach the ground?
I dumped over Karachi before, without any reports of fuel reaching the surface. That said, it was Karachi, so the locals probably wouldn't have known falling jet fuel from the daily smog...
Cue the (probably apocryphal) story of the N-registered Boeing - I forget the carrier or the type - that declared things were going pear-shaped climbing out of Heathrow to the west, and an intention to dump fuel with immediate effect. When informed that dumping fuel over Windsor Castle was verboten, the laconic reply was to inquire if Her Majesty would rather have an unexpected delivery of fuel, or accept unexpected delivery of the whole aircraft.
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