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88 votes

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

It was only very slightly higher than our plane by mere meters. You think you saw a plane at the exact same vertical level as yours, when in fact it was at least 300 metres (1000 feet) above or below ...
60levelchange's user avatar
70 votes

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

This is an excellent question, and helps illuminate several important aspects of the way perception works in aviation. But first... Any near-miss or other air-proximity incident would have been ...
Daniele Procida's user avatar
25 votes
Accepted

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

You didn't mention which country or jurisdiction you're asking about, but in the US 14 CFR 91.113(b) says: When weather conditions permit, regardless of whether an operation is conducted under ...
Pondlife's user avatar
  • 71.8k
25 votes
Accepted

What will be the immediate action by the pilot and ATC if any plane blocks the runway while landing?

ATC will tell the landing plane to go-around. The pilot will then execute the go-around by flying the missed approach procedure as published in the airport charts. Go-arounds happen daily and are ...
Quentin H's user avatar
  • 1,880
16 votes

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

A "small" transatlantic plane probably isn't very small -- it was probably further away than you think. Compare these silhouettes (can't embed due to image rights, also can't vouch for accuracy): ...
Chris H's user avatar
  • 1,157
15 votes
Accepted

Vertical and horizontal separation between cruising and climbing aircraft

I think you may have answered your own question note the use of the word OR To my understanding, aircraft at these altitudes should always have a separation of least 1000 ft or 5 nm. If you ...
Dave's user avatar
  • 101k
14 votes
Accepted

How are aircraft separated at high altitude?

First of all, there is no such thing as a stall speed, but that is a topic of its own. The ATC system has numerous ways of dealing with keeping aircraft separated, even at high levels. Let me try to ...
60levelchange's user avatar
14 votes

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

The TCAS logic is adjusted when the aircraft is in the terminal area. It does this through the following inputs: Radio Altitude - Controls TCAS parameters when below 2350 feet AGL Landing Gear, Flaps,...
Gerry's user avatar
  • 19.9k
13 votes

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

While ATC's primary goal is to prevent collisions, it is also responsible for the efficient movement of aircraft through the airspace. That requires a strategic approach to managing air traffic to get ...
Gerry's user avatar
  • 19.9k
11 votes
Accepted

How does ATC handle changing QNH/altimeter values?

In the US, ATC simply broadcasts a notification on whatever frequency is needed. For the terminal environment, section 2-9-2 of the ATC orders says: Broadcast on all appropriate frequencies to ...
Pondlife's user avatar
  • 71.8k
10 votes

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

ATC assures separation... This is a pretty critical misconception. ATC does not necessarily provide separation, just because you are flying IFR. Let's do a quick recap of the different airspace ...
60levelchange's user avatar
9 votes

How is radar separation assured between primary and secondary targets?

Typically the surveillance information from multiple sources (PSR, SSR, ADS-B, multilateration, etc) are combined into a single "system track" using a Kalman filter. The ATM system has specific code ...
Greg Hewgill's user avatar
  • 9,152
8 votes
Accepted

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

With two runways, usually, one is dedicated to arrivals, and the other is dedicated to departures. That's the simplest way to handle separation -- only in-trail separation is involved. That's ...
user14736's user avatar
  • 126
8 votes

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

Something to note here would be that modern aircraft contain a Traffic collision avoidance system (TCAS). So pilots in both aircraft would have been notified that they were on a collision and one ...
Machavity's user avatar
  • 6,213
8 votes
Accepted

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

TCAS is sort of a fallback, last-resort system used in case all else fails. TCAS works within the scope of what happens within the next minute or so, and will require the involved aircraft to perform ...
60levelchange's user avatar
8 votes

What will be the immediate action by the pilot and ATC if any plane blocks the runway while landing?

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 That would never happen. Planes are under ATC control from the moment they ...
60levelchange's user avatar
7 votes
Accepted

Does ATC have to maintain separation on diverging aircraft?

Yes, this is allowed, subject to certain conditions. See FAA Order 7110.65 (the ATC "bible"), section 5-5-7, for the full details. ...all other approved separation may be discontinued and passing ...
pericynthion's user avatar
  • 4,640
7 votes
Accepted

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

The usual reason is, that departures from runway 16 are not allowed to climb straight ahead due to noise restrictions over downtown Zurich. Instead they need to turn left, where they cross the ...
Leelou 's user avatar
  • 200
7 votes
Accepted

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

The minimum vertical separation in a holding stack is no different from the minimal vertical separation used elsewhere. This is almost universally 1000 feet. In countries where Reduced Vertical ...
60levelchange's user avatar
7 votes
Accepted

How is radar separation assured between primary and secondary targets?

Mode C transponders only transmit a squawk code (same as mode A) and altitude, so the range error due to slant distance is the same for SSR as for PSR, and the two can be easily merged. Mode S adds ...
StephenS's user avatar
  • 27.7k
7 votes

How to determine the traffic avoidance manuver?

In Scenario A there is no obvious answer. You take whatever action is necessary to avoid a collision. If this were a controlled airfield there would be questions raised to the ground controller. If ...
Jamiec's user avatar
  • 33.3k
7 votes
Accepted

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

When you are on short final and something is on, is entering, or even seems to be entering the runway, you execute a go around. As for the second part of your question, given the loose parameters I'...
Jpe61's user avatar
  • 28.8k
7 votes

Why does DME colocated with VOR require more separation?

The change appears to be clarifying that if the 15 NM distance determination is based on ground distance, for example the aircraft has passed a fix which is known to be farther than 15 NM from the VOR,...
randomhead's user avatar
  • 15.3k
7 votes

What are the separation requirements on the ground?

Except in relation to active runways, the FAA defines no specific minimum separation between aircraft operating on the ground. JO 7110.65 paragraph 2–1–1 states that "the primary purpose of the ...
randomhead's user avatar
  • 15.3k
6 votes
Accepted

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

Seems understandable to me. It may be more clear with commas... "(a) when landing, a flying machine or glider must leave clear, on its left, any aircraft which has landed, is already landing or is ...
user33214's user avatar
  • 126

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