San Diego: Two jets in formation with independent on/off trails [Fuel Dump]

Mick West

Administrator
Staff member

By SoCalSkywatch
Thursday, April 24, 2014 View from Old Town, San Diego, CA - Two military "fighter" jets flew east over Ocean Beach, Mission Hills and Hillcrest neighborhoods while releasing unknown sprays. The planes flew in close proximity to each other and turned the sprays off and on independently proving these are not contrails. Today was a heavy spray day with continuous high altitude tanker jets and these low altitude releases as caught on video here.
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[UPDATE: It's a fuel dump. The F/A-18 has fin mounted fuel vents, which accounts for the wide trail separation, lack of gap, and the on/off behaviour]



Video caption gives the time as 4/24/2014 5:08pm









Probably F/A-18s from the Marine Corps Air Station in Miramar?
 
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SR1419

Senior Member.
"low altitude" ? You can barely see the planes...and you can't tell if the contrails even persisted or not.
 

CapnPegleg

Member
Ha! I work across the street from Miramar, see these guys daily. Did notice the close formation flying.

There are some fantastic contrails around here some days, but certainly most aren't from the base.
 

TWCobra

Senior Member.
I am struggling to identify these jets. The engines appear to be wing mounted so maybe two B1s but the tail configuration seems wrong.
 

TWCobra

Senior Member.
The distance between the two contrail streams seems too large for the Hornet. There is a huge gap there. Also the nose seems to be too far forward. The radome is reflective while the rest of the aircraft isn't. However the trailing edge of the wing seems too straight for the Flanker although that may be camera angle. Interesting.
 

deirdre

Senior Member.
? bold mine http://www.blueangels.navy.mil/show/faq.aspx


How do you produce the smoke, and why do you use it?

The smoke is produced by pumping biodegradable, paraffin-based oil directly into the exhaust nozzles of the aircraft where the oil is instantly vaporized into smoke. The smoke provides a traceable path for spectators to follow, so they can see the flight profile that has been flown. It also enhances safety of flight by providing a valuable means by which the solo pilots can see each other during opposing maneuvers and conditions of lowered visibility or haze. The smoke poses no hazard to the environment.
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Back before top gun school closed at mirmar they had just about every fighter to use for training as advasaries. And in the summer the blue angles would put on a show. Also demonstrations of most american aircraft. B1 flyby was probably my fav. Others with the confederate airforce like B17s P51s You can see just about any aircraft in the San Diego skys.
 

Mick West

Administrator
Staff member
Quite an interesting system, there's a vent on the outside of the fin that directs air into the fuel dump outlet, which will possibly help suck it out, but will certainly propel it away from the plane, avoiding it igniting (which is another reason it's up on the fins)
 

Mick West

Administrator
Staff member
Fuel dumped at altitude evaporates rapidly, and never hits the ground. It's not like it's raining down - it basically come out in an aerosolized mist, which is suspended in the air, then it evaporates within minutes into a gas.
 

WeedWhacker

Senior Member
Fuel dumped at altitude evaporates rapidly, and never hits the ground. It's not like it's raining down - it basically come out in an aerosolized mist, which is suspended in the air, then it evaporates within minutes into a gas.

Yes. Exactly.

Many people do not realize just how VAST the atmosphere is, sometimes. I think it might be because people are used to personal, and very specific instances of "fumes" that they might inhale....in enclosed spaces.
 

deirdre

Senior Member.
Yes. Exactly.

Many people do not realize just how VAST the atmosphere is, sometimes. I think it might be because people are used to personal, and very specific instances of "fumes" that they might inhale....in enclosed spaces.
I don't care about fumes, I care about gasoline raining down on my head and clean windows. but it doesn't do that so I'm good now.
 

WeedWhacker

Senior Member
I don't care about fumes, I care about gasoline raining down on my head and clean windows. but it doesn't do that so I'm good now.

Again....if you are referring to a jet that is "dumping" fuel? It's not "gasoline" of course, which you know.

It is a version of kerosene. And, as you know, it is diluted immediately when dispersed. Really, and I have no scientific accuracy here to claim this, but IF you are in your car, stuck in traffic, and right behind a big diesel truck that is idling...and your air conditioning system of YOUR car is sucking in the fumes from that truck's exhaust? THEN it is a focused, and very obvious event (the smell is also obvious).

In those situations, set your AC controls to 'MAX'...or to "ReCirc" (depending on the label in your vehicle). This will eliminate the outside air, and only recirculate your car's internal air....until you move away from the offending vehicle, and can then allow fresh outside air to again enter your cabin/occupancy area.

Savvy?
 

pseacraft

Active Member
The EA-18G Growler is the Electronic Warfare configured platform. It's the direct replacement of the EA-6B hence the "EA" which is Electronic Attack in my working language. I find it amusing that the XX-18 Family does fuel dumps...the thing is a fuel whore and you almost never see one airborne without at least one belly tank. If you do see one with out an external fuel tank it isn't airborne for very long...

Also, not sure what the silly person thinks low altitude is as the video clearly shows them at a significant altitude. Plus there are FAA restrictions on dumping fuel below certain altitudes unless its a very dire situation.
 

TWCobra

Senior Member.
Thanks for finding that Mick... I was wracking my brain trying to find an answer there. The "contrail" made no sense at all.
 
J

Joe

Guest
Seems like a lot of fuel ? I could see in a emergency dumping fuel but what would be the point ? Im going to put one in my car and try it next time Im on I-95 once it gets below $ 2:50 a gallon :)
 

deirdre

Senior Member.
Seems like a lot of fuel ? I could see in a emergency dumping fuel but what would be the point ? Im going to put one in my car and try it next time Im on I-95 once it gets below $ 2:50 a gallon :)
I think you have to be lighter to land.
 
J

Joe

Guest
I think you have to be lighter to land.
Well I guess someone overfilled the tank then ? I thought they calculate the fuel needed a little closer ? I could see a little dump but that seemed like a lot of fuel .
 

deirdre

Senior Member.
Well I guess someone overfilled the tank then ? I thought they calculate the fuel needed a little closer ? I could see a little dump but that seemed like a lot of fuel .
that's what I thought but if its an aerosol its less than it looks. don't quote me but I think for some reason you need to be xtra heavy to take off. but yea I think they should have just flown around longer to burn fuel, flew over some parks, the kids would have loved it!
 
J

Joe

Guest
that's what I thought but if its an aerosol its less than it looks. don't quote me but I think for some reason you need to be xtra heavy to take off. but yea I think they should have just flown around longer to burn fuel, flew over some parks, he kids would have loved it!
yea I have to pay 25 dollars to see the Blue Angels in May ? http://veroairshow.com/
 

TWCobra

Senior Member.
It was probably either a return to base ahead of time due to some malfunction with one of the aircraft or a requirement to actually use the system for a pilot doing a type conversion. It would not happen often with these aircraft.
 

pseacraft

Active Member
Its very odd to me to see an XX-18 dumping fuel. One could always contact MCAS Miramar PAO or NAS North Island PAO depending on where they landed and ask why, possibly training but I think that would happen over the range area off shore. Military fuel dumps happen more often than you think usually with the larger aircraft. We have set volumes for our various fuel loads depending on the expected mission duration. We dump fuel more often than I like because our fuel is bloody expensive but we can not land above a certain weight and the bus driver drinks too much coffee me thinks...

Did you notice that all the pics of the XX-18 dumping fuel they are upside down? We were just joking about that...
 

Leifer

Senior Member.
It was probably either a return to base ahead of time due to some malfunction with one of the aircraft or a requirement to actually use the system for a pilot doing a type conversion. It would not happen often with these aircraft.

.....or if the training or test mission was scrubbed early, because another scheduled part of the mission was unable to participate.
Hypothetical of course.....for example: If they wanted to test a guided missile from the jet to hit a moving Remote Controlled target.....and that RC object failed to operate correctly. (just a guess)
 

Jason

Senior Member
[UPDATE: It's a fuel dump. The F/A-18 has fin mounted fuel vents, which accounts for the wide trail separation, lack of gap, and the on/off behaviour]
Maybe this has been answered already but I couldn't find it. Why would these pilots have to dump fuel, simultaneously? I could understand if one plane had a malfunction and needed to dump, but for both thats hard to believe. Also, don't these fighter jets regularly land with fuel in their tanks. I thought fuel dumping was a thing of the past, and was to only be done in an emergency situation prior to landing the aircraft.
Fuel dumped at altitude evaporates rapidly, and never hits the ground. It's not like it's raining down - it basically come out in an aerosolized mist, which is suspended in the air, then it evaporates within minutes into a gas.
How exactly does Kerosene evaporate in the upper atmosphere where temperatures are sub freezing?
 

Mick West

Administrator
Staff member
Maybe this has been answered already but I couldn't find it. Why would these pilots have to dump fuel, simultaneously? I could understand if one plane had a malfunction and needed to dump, but for both thats hard to believe. Also, don't these fighter jets regularly land with fuel in their tanks. I thought fuel dumping was a thing of the past, and was to only be done in an emergency situation prior to landing the aircraft.

Either they were
A) Practicing
B) Testing
C) Needed to return early with full tanks.

I think A) is most likely, and I don't know if C) is even an issue

How exactly does Kerosene evaporate in the upper atmosphere where temperatures are sub freezing?

Same way water does in cold weather.



It will evaporate faster if it's warmer, but basically if something is in liquid form, and in an unsaturated environment (relative to that substance), then it will evaporate.
 

Jazzy

Closed Account
Many people do not realize just how VAST the atmosphere is
Approximately equivalent to five hundred million cubic miles at normal pressure and temperature. If you counted them at the rate of one cubic mile per second, it would take you sixteen years.

I love recounting this. It isn't infinite, after all. Annually, aviation fuel puts a ton of water into every cubic mile of Earth's atmosphere, but that's a lot less water than is there already. (See below).

Density and mass


Temperature and mass density against altitude from the NRLMSISE-00standard atmosphere model (the eight dotted lines in each "decade" are at the eight cubes 8, 27, 64, ..., 729)
Main article: Density of air
The density of air at sea level is about 1.2 kg/m3 (1.2 g/L). Density is not measured directly but is calculated from measurements of temperature, pressure and humidity using the equation of state for air (a form of the ideal gas law). Atmospheric density decreases as the altitude increases. This variation can be approximately modeled using the barometric formula. More sophisticated models are used to predict orbital decay of satellites.

The average mass of the atmosphere is about 5 quadrillion (5×10^15) tonnes or 1/1,200,000 the mass of Earth. According to the American National Center for Atmospheric Research, "The total mean mass of the atmosphere is 5.1480×10^18 kg with an annual range due to water vapor of 1.2 or 1.5×10^15 kg depending on whether surface pressure or water vapor data are used; somewhat smaller than the previous estimate. The mean mass of water vapor is estimated as 1.27×10^16 kg* and the dry air mass as 5.1352 ±0.0003×10^18 kg."
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http://en.wikipedia.org/wiki/Atmosphere_of_Earth

* So to finish the job, divide 500 million into 1.27x10^16 (Kg!) = 2.54x10^4 = 25,400 tonnes per cubic mile.

One might ask, if one adds a twenty-five thousandth part to something, will it change much? :)

.
 
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WeedWhacker

Senior Member
Annually, aviation fuel puts a ton of water into every cubic mile of Earth's atmosphere, but that's a lot less water than is there already. (See below).

Gorgeous information, and thanks! Something to add to my quiver of "fact arrows", when discussing the myth, the hoax, the Urban Legend that are "chem"trails!
 
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