# What is this thing on this plane? **URL:** \ **Category:** Factual Questions\ **Created:** [July 10, 2007, 10:20pm UTC](https://boards.straightdope.com/t/what-is-this-thing-on-this-plane/411271 "2007-07-10T22:20:14Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Hanna](https://avatars.discourse-cdn.com/v4/letter/h/b3f665/32.png) [@Hanna](https://boards.straightdope.com/u/Hanna)\ **Post date:** [July 10, 2007, 10:20pm UTC](https://boards.straightdope.com/t/what-is-this-thing-on-this-plane/411271/1 "2007-07-10T22:20:14Z")
I was walking in the park and looked up and saw this: [Thing on Air Force plane](http://home.comcast.net/~ladidah1//afplane.jpg). I don’t usually notice planes but it looked different from the normal jet going over. ---
**Author:** ![Galwegian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/galwegian/32/3426_2.png) [@Galwegian](https://boards.straightdope.com/u/Galwegian)\ **Post date:** [July 10, 2007, 10:23pm UTC](https://boards.straightdope.com/t/what-is-this-thing-on-this-plane/411271/2 "2007-07-10T22:23:23Z")
Radar. > **[Airborne Warning and Control System](https://en.wikipedia.org/wiki/AWACS)** > > Airborne Warning and Control System, or AWACS, may refer to: ---
**Author:** ![DanBlather](https://avatars.discourse-cdn.com/v4/letter/d/f4b2a3/32.png) [@DanBlather](https://boards.straightdope.com/u/DanBlather)\ **Post date:** [July 10, 2007, 10:24pm UTC](https://boards.straightdope.com/t/what-is-this-thing-on-this-plane/411271/3 "2007-07-10T22:24:12Z")
That’s an [AWAC](http://en.wikipedia.org/wiki/AWAC) plane. ---
**Author:** ![Pork\_Rind](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pork_rind/32/111_2.png) [@Pork\_Rind](https://boards.straightdope.com/u/Pork_Rind)\ **Post date:** [July 10, 2007, 10:24pm UTC](https://boards.straightdope.com/t/what-is-this-thing-on-this-plane/411271/4 "2007-07-10T22:24:23Z")
[QUOTE=Boscibo] I was walking in the park and looked up and saw this: [Thing on Air Force plane](http://home.comcast.net/~ladidah1//afplane.jpg). I don’t usually notice planes but it looked different from the normal jet going over. [/QUOTE] It’s an Air Force E-3 Sentry AWACS jet based off the 707. The dish on back is a big honkin’ radar unit. [Here](http://en.wikipedia.org/wiki/AWACS)’s what Wikipedia says: > [@](#): > > he Airborne Warning and Control System (AWACS) is an aircraft system designed to carry out surveillance, and C2BM (command and control, battle management) functions. ---
**Author:** ![N9IWP](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/n9iwp/32/3154_2.png) [@N9IWP](https://boards.straightdope.com/u/N9IWP)\ **Post date:** [July 10, 2007, 10:24pm UTC](https://boards.straightdope.com/t/what-is-this-thing-on-this-plane/411271/5 "2007-07-10T22:24:31Z")
If you are talking about the disc on top, it is a RADAR system. > **[Airborne Warning and Control System](https://en.wikipedia.org/wiki/AWACS)** > > Airborne Warning and Control System, or AWACS, may refer to: Brian ---
**Author:** ![Robot\_Arm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robot_arm/32/18280_2.png) [@Robot\_Arm](https://boards.straightdope.com/u/Robot_Arm)\ **Post date:** [July 10, 2007, 10:26pm UTC](https://boards.straightdope.com/t/what-is-this-thing-on-this-plane/411271/6 "2007-07-10T22:26:12Z")
The aircraft is an [E-3 Sentry](http://en.wikipedia.org/wiki/E-3_Sentry). The large disk contains a radar antenna. ---
**Author:** ![jnglmassiv](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@jnglmassiv](https://boards.straightdope.com/u/jnglmassiv)\ **Post date:** [July 10, 2007, 10:26pm UTC](https://boards.straightdope.com/t/what-is-this-thing-on-this-plane/411271/7 "2007-07-10T22:26:44Z")
More on the E-3: [http://www.af.mil/factsheets/factsheet.asp?fsID=98](http://www.af.mil/factsheets/factsheet.asp?fsID=98) > **[Boeing E-3 Sentry](https://en.wikipedia.org/wiki/E-3_Sentry)** > > The Boeing E-3 Sentry is an American airborne early warning and control (AEW&C) aircraft developed by Boeing. E-3s are commonly known as AWACS (Airborne Warning and Control System). Derived from the Boeing 707 airliner, it provides all-weather surveillance, command, control, and communications, and is used by the United States Air Force, NATO, French Air and Space Force, Royal Saudi Air Force and Chilean Air Force. The E-3 has a distinctive rotating radar dome (rotodome) above the fuselage. ... ---
**Author:** ![sturmhauke](https://avatars.discourse-cdn.com/v4/letter/s/e47c2d/32.png) [@sturmhauke](https://boards.straightdope.com/u/sturmhauke)\ **Post date:** [July 10, 2007, 10:26pm UTC](https://boards.straightdope.com/t/what-is-this-thing-on-this-plane/411271/8 "2007-07-10T22:26:52Z")
I know a guy that flew one of those, until he was discharged for a knee injury. Can’t work the rudder pedals with a bum knee. ---
**Author:** ![garygnu](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/garygnu/32/2924_2.png) [@garygnu](https://boards.straightdope.com/u/garygnu)\ **Post date:** [July 10, 2007, 10:27pm UTC](https://boards.straightdope.com/t/what-is-this-thing-on-this-plane/411271/9 "2007-07-10T22:27:14Z")
I think that’s some kind of Radar-thing. ---
**Author:** ![Hanna](https://avatars.discourse-cdn.com/v4/letter/h/b3f665/32.png) [@Hanna](https://boards.straightdope.com/u/Hanna)\ **Post date:** [July 10, 2007, 10:29pm UTC](https://boards.straightdope.com/t/what-is-this-thing-on-this-plane/411271/10 "2007-07-10T22:29:33Z")
Cool, thanks! I’ve never seen one of those before.I figured it was probably some sort of radar or (I’ve heard of this) a hitchhiking engine, but aren’t those usually carried under the wing? ---
**Author:** ![Galwegian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/galwegian/32/3426_2.png) [@Galwegian](https://boards.straightdope.com/u/Galwegian)\ **Post date:** [July 10, 2007, 10:32pm UTC](https://boards.straightdope.com/t/what-is-this-thing-on-this-plane/411271/11 "2007-07-10T22:32:13Z")
Boscibo, what on earth is a hitchhiking engine? Do you mean an engine that’s being transported as cargo? ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [July 10, 2007, 10:33pm UTC](https://boards.straightdope.com/t/what-is-this-thing-on-this-plane/411271/12 "2007-07-10T22:33:16Z")
Snakes! I’m sick of 'em. ---
**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\ **Post date:** [July 10, 2007, 10:33pm UTC](https://boards.straightdope.com/t/what-is-this-thing-on-this-plane/411271/13 "2007-07-10T22:33:22Z")
[QUOTE=Pork Rind] The dish on back is a big honkin’ radar unit. [/QUOTE] Which can detach from the aircraft and fly into orbit to confuse the Klingons. ---
**Author:** ![St\_Ides](https://avatars.discourse-cdn.com/v4/letter/s/ccd318/32.png) [@St\_Ides](https://boards.straightdope.com/u/St_Ides)\ **Post date:** [July 10, 2007, 11:28pm UTC](https://boards.straightdope.com/t/what-is-this-thing-on-this-plane/411271/14 "2007-07-10T23:28:52Z")
[QUOTE=Galwegian] Boscibo, what on earth is a hitchhiking engine? Do you mean an engine that’s being transported as cargo? [/QUOTE] An extra engine in a dummy pod, being transported to the destination, usually for another aircraft. [On a 707](http://www.airliners.net/open.file/0226374/M/) [On a 747](http://www.airliners.net/open.file/0032654/M/) There are better pictures out there, but my search-fu is weak. ---
**Author:** ![Loach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/loach/32/350_2.png) [@Loach](https://boards.straightdope.com/u/Loach)\ **Post date:** [July 10, 2007, 11:32pm UTC](https://boards.straightdope.com/t/what-is-this-thing-on-this-plane/411271/15 "2007-07-10T23:32:49Z")
Going out on a limb here but I think its some sort of radar. ---
**Author:** ![jayjay](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jayjay/32/6765_2.png) [@jayjay](https://boards.straightdope.com/u/jayjay)\ **Post date:** [July 11, 2007, 12:10am UTC](https://boards.straightdope.com/t/what-is-this-thing-on-this-plane/411271/16 "2007-07-11T00:10:52Z")
It’s Radar, by Duran Duran. ---
**Author:** ![IAmNotSpartacus](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@IAmNotSpartacus](https://boards.straightdope.com/u/IAmNotSpartacus)\ **Post date:** [July 11, 2007, 2:11am UTC](https://boards.straightdope.com/t/what-is-this-thing-on-this-plane/411271/17 "2007-07-11T02:11:00Z")
[QUOTE=Loach] Going out on a limb here but I think its some sort of radar. [/QUOTE] I’ll have to agree here, probably some form of AWACS ---
**Author:** ![brewha](https://avatars.discourse-cdn.com/v4/letter/b/91b2a8/32.png) [@brewha](https://boards.straightdope.com/u/brewha)\ **Post date:** [July 11, 2007, 2:24am UTC](https://boards.straightdope.com/t/what-is-this-thing-on-this-plane/411271/18 "2007-07-11T02:24:26Z")
I believe it is a **R** adar **I** n earth **O** rbit. Ortherwise known as RIO if that helps. ---
**Author:** ![Loach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/loach/32/350_2.png) [@Loach](https://boards.straightdope.com/u/Loach)\ **Post date:** [July 11, 2007, 2:30am UTC](https://boards.straightdope.com/t/what-is-this-thing-on-this-plane/411271/19 "2007-07-11T02:30:56Z")
[QUOTE=IAmNotSpartacus] I’ll have to agree here, probably some form of AWACS [/QUOTE] [cite](http://boards.straightdope.com/sdmb/showpost.php?p=8765810&postcount=3) ---
**Author:** ![Ruby](https://avatars.discourse-cdn.com/v4/letter/r/13edae/32.png) [@Ruby](https://boards.straightdope.com/u/Ruby)\ **Post date:** [July 11, 2007, 2:51am UTC](https://boards.straightdope.com/t/what-is-this-thing-on-this-plane/411271/20 "2007-07-11T02:51:16Z")
I’m thinkin’ rada…no Arbys! As an aside, I had no idea that planes transported extra engines on the exterior of the aircraft, especially on the wing! Wouldn’t the plane tend to list to one side? [Next page](https://boards.straightdope.com/t/what-is-this-thing-on-this-plane/411271.md?page=2)