Forum: Civil and General Aviation

when I was plane watching at my home in [Link pending approval], about 3 months apart I saw an Airbus 340 Lufthansa Airlines and a Boeing 747 United Airlines flying together A340 in front of Boeing 747 and A340 with contrails and 747 without them. They must have been 150-250 feet apart.

Does anyone know why? And that's not to mention all the KC-10s, KC-135s, F-15s, F-16s, and A-10s over my house.

thanks

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Quote:

they must have been 150-250 feet apart

I'd be wondering what in the *&^% two commercial passenger heavies were doing that close together!!!

I too was wondering what two airliners would be doing that close together. Here in Japan (VFR all altitudes) we are supposed to maneuver off of CATA by ten miles so as not to trip their TCAS, and it still happens, so I'd venture that a 150 foot pass would cause some pretty hefty resolution advisories to the flightdecks of both aircraft.

An A340 with a 747 300 feet in trail? Did the Boeing follow the Airbus during the whole approach? Unless it was the FAA or NASA that should NEVER happen. Wake turb alone would shake the Boeing pretty violently. Perhaps they had some vertical sep (Boeing's higher) and there was just a misperception of horizontal distance? TRACON should keep in-trail traffic seperated by at least 2 miles, I believe. Or maybe it's 1 mile with the new precision nav technology. Gotta check the FAR on that one but that's the number that rings a bell.

Don't know what exit you're on in Jersey ( Wink

) but the military stuff could be staging in and out of McGuire. It's an important east coast staging base before jumping the pond.

Sounds like icing test to me. That would explain the close distance and perhaps the 'contrails', but that would be a single 'contrail' typically...

Kevin
The Ejection Site

kmceject, that sounds reasonable, but wouldn't they use agency aircraft or at least conduct tests like those over unpopulated areas? He said he saw the airlines' markings and that he was watching them from his back yard. I'm wondering how he was seeing contrails at an altitude low enough to see markings. Maybe they were vapor in the wing voritces?

AFAIK, FAA and/or NASA uses KC-135s or KC-10s as the sprayer in icing tests. Not Airbus, definately not in civvy livery, and most certainly never over populated areas. Jersey's close enough to the ocean to do overwater icing tests. Need more context info on this one. Would be good to get a photo on the next occurance, since he said he's seen it before.

The "contrails" were indeed probably low pressure vapes off the Lufty's wings.

1. linkf-16simdude-It was not from the wings there were four and it was coming from the engines and I'll try to get a pic next time to show you.

2. Parrothead-I know alot about planes and can name any plane and airline when their tiny dots in the sky I can identify them just from there contrails and I always have my binoculars when plane watching.

3. I saw them once over Sandy Hook and once over my house in Wall [Link pending approval]
and they where not from McGuire or NASA.

1: if he saw conning from the engines then they were pretty high up

2: if they were pretty high up how did he determine they were only 150-250 feet apart?

habu2 wrote:

1: if he saw conning from the engines then they were pretty high up

2: if they were pretty high up how did he determine they were only 150-250 feet apart?

.....and if both of those are true, how did he determine they were a Lufty and a United? Confused

Is it possible to get condensation vapes around the engine nacelles at low altitude?

Any closer they would have crashed into eachother. They definitely were not more then 500 feet even if they were high up.

falconpilot wrote:

Any closer they would have crashed into eachother. They definitely were not more then 500 feet even if they were high up.

Given the assumption that conns are seen only at high altitude (therefore you're looking up at them), there is an outside possiblity that they were seen to be pretty close horizontally (500 ft. as you say) but vertically seperated, giving the illusion a collision was imminent. For jet routes, traffic is vertically seperated by at least 2000 feet. So even though it may have looked like they were close, there was still a goodly bit of air between 'em.

And if that's the case, I'm impressed that you could make out the livery of each one at cruise altitude!

Simdude, I don't know what it is with you telling me about livery like I'm lying about it as if that would make a difference about their distance. You mention the livery ever time you write.

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Calm down falconpilot. I'm not accusing you of anything. We trying to answer your question with the details you gave us.

You told parrothead "I know alot about planes and can name any plane and airline when their tiny dots in the sky I can identify them just from there contrails and I always have my binoculars when plane watching." That's a great skill. Since you said the contrails were off the engines then it had to be at cruise altitude as that's where contrails happen. If you can ID a particular airline's paint scheme from 35000 feet you have better eyes than most of us. What I'm saying is that even at high altitudes, a 500 foot horizontal seperation is an air traffic control violation EXCEPT if the two jets are vertically seperated by 2000 feet or more.

And to answer your question of "livery", that's another name for the paint scheme and logos each jet wears.

Forum: Civil and General Aviation

Seen this two times now - Airliners flying close together