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Questions tagged [separation]

Questions regarding the distance separating aircraft during flight.

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Does separation happen easier with less dense air?

Does less dense air affect when separation happens? So if you have a cylinder traveling in a straight path like the one above, there is separation happening at a given speed. If you were to change ...
Wyatt's user avatar
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1 vote
1 answer
78 views

Separation between aircraft changing flight level and aircraft flying on the same track at that flight level

I've read in "Optimization of aircraft trajectories over the North Atlantic Airspace" and saw that in the separation standards, the longitudinal separation when changing the flight level is ...
Lê Minh Hoàng's user avatar
-1 votes
1 answer
47 views

Does the pressure recovery on an airfoil cause separation more with turbulent BL’s?

If you have a turbulent boundary layer going through pressure recovery on an airfoil, why is it more likely to separate than a laminar boundary layer? From my research/intuition I think turbulent ...
Wyatt's user avatar
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0 votes
2 answers
113 views

Is there any instrument on board to assure horizontal collision avoidance?

I know that TCAS are used to get 'Traffic Alerts' as well as 'Resolution Advisories'. But an RA seems to only provide instructions to avoid vertical collisions. How about the horizontal separation, ...
Smile LiaZ's user avatar
0 votes
0 answers
81 views

Does airbrake reduce or increase static pressure downstream of it?

When airbrake is down, flow is fully attached on upper surface, when airbrake lift up flow separate. Is static pressure at point 2 and 3 now lower or higher compare when airbrake is down? CFD video ...
22flower's user avatar
  • 1,958
6 votes
2 answers
422 views

How do IFR flights in IMC in Class G airspace not collide?

According to Wikipedia, in Class G airspace, "Operations may be conducted under IFR or VFR. ATC has no authority but VFR minimums are to be known by pilots. Traffic Information may be given as ...
Someone's user avatar
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7 votes
2 answers
919 views

What are the separation requirements on the ground?

What are the FAA regulations for aircraft separation on the ground, outside of active runways?
Anonymous Physicist's user avatar
3 votes
1 answer
1k views

Is the published recommendation on when to turn crosswind dangerous?

Citing the FAA from Airplane Flying Handbook On the departure leg after takeoff, the pilot should continue climbing straight ahead and, if remaining in the traffic pattern, commence a turn to the ...
user's user avatar
  • 358
2 votes
1 answer
539 views

Why does DME colocated with VOR require more separation?

In earlier versions of ICAO Doc 4444 (Amendment 9 and earlier), two aircraft were deemed to be laterally separated if they were departing a VOR on radials which diverged by at least 15 degrees and if ...
omprakash khamitkar's user avatar
0 votes
2 answers
936 views

What is the vertical separation minima between IFR and VFR?

ICAO Doc 4444, 5.3.2 says The vertical separation minimum (VSM) shall be: a) a nominal 300 m (1 000 ft) below FL 290 and a nominal 600 m (2 000 ft) at or above this level, except as provided for in b)...
Sisir Simha's user avatar
11 votes
3 answers
2k views

How does a TCAS system avoid unnecessary (RAs) resolution advisories when aircraft are operating on separate closely spaced parallel runways?

How does a TCAS system avoid unnecessary (RAs) resolution advisories when aircraft are operating on separate closely spaced parallel runways (e.g. 2500 feet or less separation between rwy centerlines)....
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1 vote
3 answers
432 views

Are mode C altitude returns valid for aircraft separation?

According to FAA JO 7110.65 5-12-8 'Validation of MODE C READOUT', Mode C is valid if there is less than 300 feet deviation from the pilot reported altitude. If ATC instruct 'A' aircraft to maintain 5,...
Min's user avatar
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1 vote
2 answers
302 views

During VMC conditions in terminal airspace (class B), does the pilots have to strictly follow separation standards issued by ATC?

Is it common for pilots to breach separation standards in terminal airspace while the conditions are VMC? I'm interested primarily in commercial aircraft that have scheduled operations in major ...
distributedconscious's user avatar
3 votes
0 answers
78 views

How did lateral and longitudinal separation minima evolve?

What is the evolution in time of lateral and longitudinal separation minima?
Gin's user avatar
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3 votes
2 answers
332 views

Will there be dynamic or variable separation minima in future?

In the future, is it possible to apply in the same airspace different separations between pairs of aircraft? Depending on the relative speed, navigation capacity of the aircraft, intersection geometry,...
Paula's user avatar
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0 votes
2 answers
267 views

How to find runway Centerline spacing on airport diagrams?

I know that airport diagrams show the exact position of airport runways in DMS (degrees, minutes, seconds) and therefore could use trigonometry to find how far apart runway centerlines are from ...
WildGurgs36's user avatar
0 votes
1 answer
181 views

Which avoidance maneuver is best when seeing crossing traffic on approach to a runway?

Let us say I am in final landing and I saw another aircraft is crossing the runway while I am still in air, should go around be my best choice? If I touched down and then I saw the traffic, how ...
VvV's user avatar
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7 votes
2 answers
772 views

Are there conventions on which side to travel on Victor airways - USA?

I'm a low-time VFR pilot (100hrs) in the United States. I have not yet started IFR training (other than XC time building). I understand the purposes and reasons why the Victor airways exist. I also ...
Damon's user avatar
  • 173
3 votes
2 answers
201 views

Is there any current and/or upcoming technology that alerts Air Traffic Controllers in case of loss of aircraft separation?

Currently doing an assignment and it to analyse an accident where older atc systems could have been at fault. In 1995 there was an incident where two aircraft came closer than the then current ...
Pitttypit's user avatar
3 votes
3 answers
617 views

How to determine the traffic avoidance manuver?

Scenario A: I started the takeoff roll and then noticed another aircraft is crossing the runway in front of me, how could I determine what is the best avoidance maneuver, like full braking to abort ...
VvV's user avatar
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11 votes
6 answers
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What will be the immediate action by the pilot and ATC if any plane blocks the runway while landing?

Suppose, if the Airport has only one runway and one plane is trying to take off at the end of the runway and other plane trying to land from the other end of the runway. Due to any reason if the ...
Deepak-MSFT's user avatar
3 votes
0 answers
95 views

What is the FAA regulation for the 3 mile / 1,000' separation for a commercial airliner? [duplicate]

I need help finding the Number/Citation for the FAA regulation/order that states commercial airliner separation should usually be at least 3 miles laterally, or 1,000 feet vertically. I cannot find ...
kjb's user avatar
  • 31
5 votes
1 answer
412 views

Is separation provided in class F airspace?

According to the Wikipedia page on different airspace classes, separation is provided for IFR/SVFR to other IFR/SVFR in class F airspace. In ICAO Annex 11 from 2018 (p.36 in the pdf file), I can't ...
psie's user avatar
  • 217
11 votes
5 answers
4k views

How is radar separation assured between primary and secondary targets?

Air traffic control radars come in two flavours, with most ATC centers using both and displaying the output of both on a single screen: Primary surveillance radar (PSR) is a true radar system, which ...
Vikki's user avatar
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1 vote
1 answer
364 views

How does the ICAO VOR separation apply to reciprocal radials?

If two aircraft are on VOR radials that are apart by 15 degrees or more and one aircraft is at least 15 DME out, they are considered laterally separate. I read this rule in ICAO documents but my ...
Hafiz Kashif Amin's user avatar
6 votes
1 answer
735 views

What does "zero offset between two waypoints" mean in ICAO Doc 4444?

My question is with reference to the GNSS based separation specified in ICAO Doc 4444. Could someone explain the significance/meaning of the condition "zero offset between two waypoints" criteria? if ...
user37214's user avatar
6 votes
2 answers
1k views

Why do planes above FL290 need more vertical spacing?

At altitudes no higher than 29,000 feet, planes need only 1,000 feet of vertical separation. However, planes over FL290 need twice that, i.e. they need 2,000 feet of vertical spacing between them and ...
WildGurgs36's user avatar
6 votes
3 answers
770 views

What vertical separation is required in a holding stack to avoid wake turbulence?

Sometimes in my free time I play Endless ATC, a game where one acts as the approach and departure controller. In the game (as in real life) the controller is forced to put planes in a holding stack, ...
WildGurgs36's user avatar
6 votes
4 answers
1k views

Why do heavy departures wait 5-10 minutes on the runway at ZRH?

I'm frequently travelling to Zürich for business and I usually make my schedule so that I have at least an hour to do some planespotting and photographing at the ZRH airport. Whenever I came to the ...
vtomic85's user avatar
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3 votes
2 answers
1k views

Why are both ATC and TCAS tasked to prevent collisions although TCAS takes precedence anyway?

« The primary purpose of ATC worldwide is to prevent collisions [...] Many aircraft also have collision avoidance systems, which provide additional safety by warning pilots when other aircraft get ...
summerrain's user avatar
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3 votes
1 answer
189 views

What would be a safe minimum vertical separation distance between passenger-carrying multicopter aircraft?

There is increasing talk about employing passenger-carrying multicopters ("taxi drones") to extend urban mobility into the third dimension. These aircraft will have MTOMs in the range of several ...
Monolo's user avatar
  • 1,687
3 votes
2 answers
755 views

Is the Tower (Local) Controller responsible for "separating" VFR traffic in the pattern in the U.S. in Class D airspace?

For example, in U.S. Class D airspace, if an inbound aircraft operating VFR is instructed by the Control Tower to "enter left downwind for runway 18, report entering downwind," is the controller ...
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11 votes
1 answer
1k views

Vertical and horizontal separation between cruising and climbing aircraft

I was recently a passenger on a commercial aircraft at cruise altitude when I noticed another aircraft just reaching its cruising altitude while crossing our flightpath from below, at what looked like ...
Daniel Hutmacher's user avatar
5 votes
1 answer
719 views

Is true altitude vertical separation between airplanes dependent on temperature?

Does the "true" altitude vertical separation between airplanes (using the same altimeter setting) vary as the temperature changes? ( I fully realize that the "true" altitude of both airplanes is ...
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5 votes
1 answer
421 views

How close is this Su-27 to the aircraft recording the pass?

There is footage of an intercept of a US Nay recon aircraft being intercepted by a Russian Su-27: (still from the BBC video article, who look like they got it from the US Navy directly) which was ...
bertieb's user avatar
  • 153
3 votes
0 answers
166 views

Diversions because of fog: What are the reasons?

It's fog season again around my local airport MUC (EDDM), and I have noticed a number of diversions recently. Some planes were holding a bit before attempting to land, performed a go around and then ...
zebonaut's user avatar
  • 131
5 votes
2 answers
599 views

Can RVSM safely be further reduced?

Since the world population shows no signs of slowing down its rapid increase, it's pretty safe to say that means we can only expect more concurrent flights as time moves forward. Is it physically ...
Cloud's user avatar
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7 votes
2 answers
801 views

What does "leave clear on its left" mean in UK regulations relating to collision avoidance on non-runway landings?

This doesn't seem to be plain English, could someone explain this with a simple example for me please? I'm not sure what 'Leave clear on it's left' means, and it's not clear whether the subject of the ...
JeffUK's user avatar
  • 193
3 votes
3 answers
2k views

How exactly do ICAO's VOR-based minimum separation standards work?

This question is aimed at Air Traffic Controllers who are familiar with ICAO Separation minima. DOC 4444 states the following: Lateral separation between two aircraft exists when: VOR: both ...
user avatar
1 vote
0 answers
83 views

What is the legal definition of separation as it relates to ATC? [duplicate]

ATC provides "separation" for all aircraft in class bravo airspace. What is the legal definition of separation? Is it the same or different than the see-and-avoid rule (FAR Part 91.113(b)) where all ...
slantalpha's user avatar
  • 4,203
1 vote
4 answers
229 views

How to make ourselves more visible to other aircraft?

What are the best practices in air to help others see our aircraft?
Toni's user avatar
  • 17
6 votes
1 answer
665 views

How is separation managed when there are only two parallel runways in a very busy airport?

In the world's busiest airports, how is separation managed between departures and arrivals when there are only two parallel runways like in London Heathrow. What is the minimum safe separation?
securitydude5's user avatar
48 votes
6 answers
37k views

How close can planes fly to each other over the ocean?

While on a recent Air Transat flight from Toronto Pearson to London Gatwick, several hours into the flight and over the Atlantic Ocean, my daughter and I noticed a plane behind ours to the left, ...
Wendy's user avatar
  • 477
1 vote
1 answer
566 views

What is the minimum separation for aircraft operating on or intersecting the same runway?

How capturing of this photo was ever possible: (photo courtesy of jetphotos.com) Shouldn't there be a bigger time / distance separation of three aircrafts using, operating or intersecting the same ...
trejder's user avatar
  • 4,162
18 votes
1 answer
11k views

How does vertical separation work above FL400?

The information mentioned in "Jeppesen Airway Manual" is that after FL400, fight levels are FL430, FL470, FL510 for the 'even' FL's column. Normally, I would expect every level divided by a thousand ...
wiaim's user avatar
  • 2,791
19 votes
2 answers
3k views

Is the pilot required to keep visual lookout during IFR operations in VMC?

During VFR operations, the pilot must always self-assure separation from other aircraft, and thus must maintain a visual lookout all the time. For IFR operations but in VMC, are there any rules as to ...
Stefan's user avatar
  • 4,692
4 votes
1 answer
214 views

How far should commercial jets be from each other when on the runway or while departing?

Does anyone know how far should a commercial jet (787,777,etc...) be away from each other in runway or in process of taking off? Are there public resources that I can look up?
T.C's user avatar
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1 vote
0 answers
188 views

Is there a "maximum" airplane count in the visible sky at a given location? [closed]

At night, I look at the planes in the sky and count them. I can normally spot between 2-5 planes, never more. As the visible sky is always a constant area and there are security distances and aerial ...
Benj's user avatar
  • 111
1 vote
0 answers
255 views

What are normal landing separation minima? [duplicate]

As far as I know we have separation minima of 10 minutes in horizontal flight, so do we have any equivalent separation minima for landing? If so, how it is possible to land two aircraft in a very ...
Meena's user avatar
  • 11
6 votes
2 answers
4k views

How are aircraft separated at high altitude?

When cruising at high altitude, a fixed-wing aircraft has less margin for adjusting its speed, due to the convergence of the stall "speed" and the overspeed limit: If and aircraft has to be separated ...
mins's user avatar
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