Rozhan 0 Report post Posted November 26, 2005 About the contrails TK. Correct me if I'm wrong, but can contrails be purposely made to occur? For many times I notice that planes will leave contrails when they are flying over or near airports, and the contrails stop occuring when it leaves the airspace after a few minutes... almost like as if it is signalling its presence. Or is it a natural occurance? Share this post Link to post Share on other sites
Denny Yen 0 Report post Posted November 26, 2005 (edited) Rozhan: I found some useful info about contrails, here are some of them:- What's the reason for contrails formation? Water vapour released from a/c freezes upon contact with extreme cold air. What's the main composition of contrails? Ice crystals. Typical temperaure at which contrails start to form? -40deg C Typical altitude of contrails formation? 28,000ft Duration of contrails? Factors that contribute to duration. A few seconds to a couple of hours. Moisture in air, wind direction and strength/speed. What a long-lasting contrail can evolve into? Cirrus cloud. Typical dimensions of contrails? 200-400m Regions with the highest frequency of contrails. N.America and Europe. What's the significance of a long-lasting contrail? Humid air high in the atmosphere = possible early storm warning. Significance of twisting contrails. Turbulence. Source: "Aircraft contrails fact-sheet" (US EPA) Edited November 26, 2005 by Denny Yen Share this post Link to post Share on other sites
Rozhan 0 Report post Posted November 26, 2005 (edited) Thanks Denny. Yes, that appears to be how contrails are formed, but I wonder if pilots can make it occur on purpose, in situations when contrails do not occur naturally. I saw planes at high altitudes giving out contrails over KK (near BKI of course), Pekan (KUA), KBR, PEN. These last just for a short while. Based on the facts you listed, perhaps pilots can purposely release water vapor to make contrails.... perhaps for signalling purpose to ATC? Edited November 26, 2005 by Rozhan Share this post Link to post Share on other sites
T Azahan 1 Report post Posted November 27, 2005 thanx danny for the insight! Share this post Link to post Share on other sites
Walter Sim 1 Report post Posted November 27, 2005 (edited) maybe dumping fuel perhaps, near airports. I notice in my 737 flights when albeit decending i think, there is this gust of air come through from the ENGINE through the wing and towards teh back of the wing. Are those contrails too? EDIT: Scrumtious food there, breakfast? TK, do you always use full flaps for landing on a 777? lets say in WMKK Edited November 27, 2005 by Walter Sim Share this post Link to post Share on other sites
TK 0 Report post Posted November 27, 2005 I dont see any way for a Pilot of an aircraft to 'make' contrails. Thanks Denny for the sources. It is well explain. I need to get more contrails. I have seen a few ones that is not in a straight line.. after the aircraft pass by..i would be able to see some kind of a waving results from such contrails...why...turbulence...temperature changes!! The air we fly on changes, like temperature and wind. It is never stable unless some High pressure systems around where we fly. Temperature changes creates such abnormal calculation to the aircraft static sensors. It will recalculates the speed and altitude we flying in as changes occurs of a mere one degrees. The air up in the sky is like a block of different temperature. We fly from a warm to cold or vice versa, as this will creates some minor chops and maybe moderate to severe if we are within the drastic temperature gap.Normally occurs somewhere around jetstream areas...we might get a good tail wind or a slow crawling head wind...plus turbulence is pressence. Between 29,000 feet up until 40,000 feet is where active winds and temperature changes, includes jet stream. 29,000 feet and below...is where the active clouds around. we need Boeing or Airbus to make a powerful plane to fly above 40,000 feet at initial climb out with full load to get away from all these messy weather! Too bad..concorde is no longer around. Share this post Link to post Share on other sites
Ibrahim 0 Report post Posted November 27, 2005 Nice.. Thank For that fact I learn New thing today. Share this post Link to post Share on other sites
Walter Sim 1 Report post Posted November 27, 2005 we all learn new things everyday! Share this post Link to post Share on other sites
Rozhan 0 Report post Posted November 27, 2005 Very nice explanation there TK, especially the blocks of different temperatures up there. I have been on a T7 at 43,000 feet and the sky looked clear and blue. The only problem is the windows gets a little frosted and taking pictures means less than clear images. Share this post Link to post Share on other sites
Denny Yen 0 Report post Posted November 27, 2005 A while ago, Azahan posted the C check pics. Ever wondered what's the difference between? I found some simple explanation about each difference: Share this post Link to post Share on other sites
Guest Fendy Report post Posted November 27, 2005 by dumping fuel, isnt that in a way making contrail>? Share this post Link to post Share on other sites
T Azahan 1 Report post Posted November 27, 2005 cool stuff denny. yes, i learn a lot today. Share this post Link to post Share on other sites
Attan 0 Report post Posted December 2, 2005 TK Thanks for the CONTRAIL series of pics. Really love them. Read somewhere that in high altitudes fine "supercooled water droplets" exist below freezing point but doesn't turn to ice. When the air is disturbed by vortices these droplets then turn into ice crystals. Similarly these droplets when they come into contact with cold metal such as an aircraft skin will turn into the powdery "rime ice". Share this post Link to post Share on other sites
Ibrahim 0 Report post Posted December 2, 2005 (edited) TK Your Capten Do THing Like This ??? And You WIpe The Scree.. Edited December 2, 2005 by Ibrahim Share this post Link to post Share on other sites
Min Chun 0 Report post Posted December 2, 2005 i saw this pic in A.net today and saved it..TK..or u r the one who climb whule ur captain wipe the screen. If u climb..remember to take a photo from there wor.. Share this post Link to post Share on other sites
Nicholas Wan 0 Report post Posted December 2, 2005 TK Your Capten Do THing Like This ??? And You WIpe The Scree.. 18479[/snapback] Hey i have seen on a 737 the capt put rain X on the wind screen...wonder approve by FAA??? Share this post Link to post Share on other sites
Min Chun 0 Report post Posted December 4, 2005 Whats raix x Nicholas? Share this post Link to post Share on other sites
Sandeep G 1 Report post Posted December 4, 2005 Whats raix x Nicholas? 18895[/snapback] its this damn cool liquid you rub on your windscreen. It creates a very fine thin film of lubricant over the windscreen, almost like silicon, and when you're driving in the rain, the rain just streams off without having to even use your windscreen wipers!!! it's awesome! I use it all the time!! In T7, i've seen pilots leaning out the side cockpit windows to clean the forward panels hahaha TK, your captain make you do also ah? Share this post Link to post Share on other sites
Gavin Andrew David 6 Report post Posted December 5, 2005 RainX Rocks . heheheh .. I just love it and cannot live without it Share this post Link to post Share on other sites
Min Chun 0 Report post Posted December 5, 2005 But if u use it once..u must use it continually right? or else ur wiper will 'cacat' when the rain x get off from the screen and u din apply it on your screen anymore.. Share this post Link to post Share on other sites
Gavin Andrew David 6 Report post Posted December 5, 2005 Really ? never experience Share this post Link to post Share on other sites
TK 0 Report post Posted December 5, 2005 It happens.... wheel change!!! Landed with one deflate tyre!! Look where the jack is... I dont need to do this wheel change Share this post Link to post Share on other sites
Guest Fendy Report post Posted December 5, 2005 fuyoh. michelin! woo hoo Share this post Link to post Share on other sites
TK 0 Report post Posted December 5, 2005 " Michelin Air X "...dont play play...wanna trade to your BMW fendy.... Share this post Link to post Share on other sites
Guest Fendy Report post Posted December 5, 2005 pimp my ride ah Share this post Link to post Share on other sites
