E3 Sentry Question
Thread Starter

Joined: Oct 2006
Posts: 2,800
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From: One Three Seven, Disco Heaven.
E3 Sentry Question
Heading back to work after lunch, I saw the distinctive large arc contrail remains of an E3 orbiting over the Borders, and sure enough, following the curve I saw it, just as it started to trail again. A couple of things I pondered over, that you guys may be able to answer. Is there an "orbit switch", that sets the aircraft up in a pre-planned orbit, or does it have to be flown manually? Everytime I have seen these over the Borders, apart from once, they are always in a right hand, (clockwise), turn. I always thought that the Captain of an aircraft, sat in the left hand seat and therefore it should be in a left hand turn/orbit, as the Captain is in charge and would need to see where the aircraft was heading. So why do the E3's, that I've seen anyway, go round in a right/clockwise turn?

Joined: Apr 2005
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From: UK
Aircraft can orbit either left or right. Either pilot can be the handling pilot but captain is usually, but not always, in the left hand seat. Autopilot has a green rating so does most of the work. Orbits orientated to get the most out of the radar system, or to get the sun out of the captain's eyes.
Many tricky decisions to make on the E-3 flightdeck, but all the time in the world to make them.
Many tricky decisions to make on the E-3 flightdeck, but all the time in the world to make them.
Thread Starter

Joined: Oct 2006
Posts: 2,800
Likes: 74
From: One Three Seven, Disco Heaven.
Thanks JTO. Heard what I thought were Typhoons, over the factory around the same time as the E3 was in the area, but they were gone by the time I got outside for a look.


Joined: Apr 2008
Aviation Qualifications: Military
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From: The Whyte House
So why do the E3's, that I've seen anyway, go round in a right/clockwise turn?
The route to the orbit will have an effect. For example, ATC vectors or mandated routing prior to the join may lead to a smoother entry in one or the other direction.
Other than that? Sun position, toss of a coin, how the crew feels on the day. Does the nav prefer to sleep with head forward (lh orbit) or head back (rh orbit).
The rumour that half way through a sortie it needs to switch direction to 'unwind' is completely unfounded. Allegedly.
Joined: Apr 2010
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From: Canada
Had an AWACS trip to see how their side of the game worked. Orbit direction was preplanned (not sure why, think it was proximity to controlled airspace vs likely main threat direction). Orbits were free-flown every so often for pilot handling practice - they even let me do one. Lots of anticipation needed, like leading a formation really.
Joined: May 2008
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From: Here
The right hand orbit is the is infact the orbit of choice for the nav. It allows him to slump back in the nav chair, thus getting a better qualtiy of sleep
! Until of course the question of tea or coffee and when to put the cumberland sausage breakfast in the oven.
! Until of course the question of tea or coffee and when to put the cumberland sausage breakfast in the oven.


Joined: Apr 2008
Aviation Qualifications: Military
Posts: 1,960
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From: The Whyte House
The right hand orbit is the is infact the orbit of choice for the nav.
Joined: Oct 2011
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From: USA
DG, don't listen to any of them. This is the wrong place for serious advice. Let me help you out. It is purely a comfort thing that comes down to being left or right handed. Most captains are right handers, hence most orbits to the right.
Joined: Oct 2011
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From: USA
Erm, I think I may have f***ed up here. I don't actually know the reason, I was hoping my answer would have been misleading, but believable. A real bu**er if I stumbled across one of the real reasons by mistake!
I'll get my coat...
I'll get my coat...

Joined: Sep 2006
Aviation Qualifications: Military
Posts: 6,024
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From: Somewhere flat
Actually its all to do with the effect of changing groundpeed and angles of bank caused by the prevailing wind velocity at height with respect to the radar CFAR circuits and the orientation to the working areas.
Not that you would expect one of the pilots to understand that.... When this used to be taught to the new Sentry crews in the days of yore, the pilot instructor on Sentry Training Squadron refused to send his students because "we have already studied met at basic flying training". Sad but true!
Not that you would expect one of the pilots to understand that.... When this used to be taught to the new Sentry crews in the days of yore, the pilot instructor on Sentry Training Squadron refused to send his students because "we have already studied met at basic flying training". Sad but true!



