If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#121
|
|||
|
|||
BA 777 crash at Heathrow
|
#122
|
|||
|
|||
BA 777 crash at Heathrow
Robert Moore wrote in
46.128: Big John wrote Before the Airlines started flying jets the Air Force ran into a fuel problem in their jets at altitude. Can't remember now if it was ice xtyls forming in the fuel or waxing as you say but the Air Force started putting an additive in their fuel that stopped that problem and the Airlines picked up on it when they started flying jets I was told. I flew the first generation jets (B-707) for the first major operator, PanAm. There was nothing in our manuals about a fuel additive being used,and we bought fuel all over the world. We used bleed air to deice the fuel filter. One minute ON every thirty minutes if Tank temp was below zero degrees centigrade or one minute ON if any icing light illuminated. However, if the tank temp dropped below three degrees centigrade above the freeze point of the particular fuel on board, the pilot was required to take one of the following actions: 1. Increase IAS to warm up the wing. 2. Descend to a warmer cruise altitude. 3 Reroute to a more southernly route. The basic problem was that the xtyls would form in the fuel and then pack the filter and stop fuel flow. The fuel filter was located between the first and second stages of the fuel pump. Any blockage of the filter opened a bypass around the fuel filter. So....a blocked filter would NOT stop the fuel flow. Actually, there were two bypasses, one as just described and a second one around both the pump first stage and the filter. I would strongly suspect that Boeing still provides at least this same level of protection for its current generation of jetliners. Nope. And I have no idea why. The A300 didn't have one either. There's certainly no control for it in the flight deck, and if there was an automatic syste, they would have had to have told us about it since a malfunction would mean an insanely high oil temp. ( I had three shutdowns in 727s due to fuel heat getting stuck on) Do the Airlines still use the/a additive in their fuel for the high altitude problem? Never did as far as I know. The corporate guys do add Prist, probably due to the much thinner wings. Yeah, I've never seen it added to an airliner's fuel either. I've a vague recollecton of seeing prist added to a lear's fuel with a special fitting on the fuel hose accepting a can of prist. But AFAIK we don't have anything. Bertie |
#123
|
|||
|
|||
BA 777 crash at Heathrow
On Tue, 18 Mar 2008 15:55:12 +0000 (UTC), Bertie the Bunyip
wrote: Yeah, I've never seen it added to an airliner's fuel either. I've a vague recollecton of seeing prist added to a lear's fuel with a special fitting on the fuel hose accepting a can of prist. But AFAIK we don't have anything. I might have this backward, just working into the jet buring world, but are you loading Jet-A or Jet-A1? Generally isn't Prist in Jet-A since it has a higher gelling point? I think Prist also has an antimicrobial effect, helps in the Jet-A stuff that doesn't fly as much as a jetliner. |
#124
|
|||
|
|||
BA 777 crash at Heathrow
Peter Clark wrote in
: On Tue, 18 Mar 2008 15:55:12 +0000 (UTC), Bertie the Bunyip wrote: Yeah, I've never seen it added to an airliner's fuel either. I've a vague recollecton of seeing prist added to a lear's fuel with a special fitting on the fuel hose accepting a can of prist. But AFAIK we don't have anything. I might have this backward, just working into the jet buring world, but are you loading Jet-A or Jet-A1? Generally isn't Prist in Jet-A since it has a higher gelling point? I think Prist also has an antimicrobial effect, helps in the Jet-A stuff that doesn't fly as much as a jetliner. We use both, depending on where we're getting it. We also get some oddball wide cut stuff in some places. It's fine, but we have to be more careful loading as it lights up pretty easily. We don't pay too much attention to what we uplift since we don't spend enough time at cruise to get it cold enough to worry about. I don't know of any additives ever added to anything i've flown. I did get a fuel blockage from water in suspension in 100LL years ago, but I think they fixed that problem. Bertie |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
[Fwd: Concord at Heathrow?] | Markus Baur | Aviation Photos | 3 | December 26th 07 11:55 PM |
B747 at Heathrow | Glenn[_2_] | Aviation Photos | 0 | December 8th 07 09:47 AM |
A380 flew into Heathrow today | Kingfish | Piloting | 82 | May 30th 06 01:55 PM |
Google Earth Heathrow 9L approach | news.east.cox.net | Piloting | 23 | April 20th 06 09:36 PM |