How close is too close for planes?

[Lynx516]

I was on a flight this morning from Heathrow and as we climbed to altitude we climbed up towards another plane which was already at height.

As we got closer to it I realised it was at a constant bearing and I could now clearly read the wording on the side of the plane. So started to get a bit worried until we levelled off below it

I would estimate it was under 1km away. I thought they needed to keep 3+ miles apart? Is this normal or was this a bit closer than intended?

[GT03ROB]

I thought it was only around 1000ft vertical separation

[Mandat]

On one of my recent trips to Los Angeles, my flight was parallel landing at LAX with another plane off to the side, which looked very close indeed.

Looking up the minimum separation just now, google says that for the most part, IFR aircraft must be separated by 3 miles laterally or 1000 feet vertically.

One exception to this rule is during parallel landing, like at LAX, where the minimum separation is only 3,600 feet (1,097m).

[LotusOmega375D]

I love looking out for other planes when I am sitting at the window of an airliner. You can see aircraft taking-off and landing at airports en route and see the other planes in your hold pattern at fairly close quarters. My most memorable close encounter was with a French Air Force Rafale, which I watched come hurtling towards us from 90 degrees to the side and shot straight underneath our 737 on our way home from the Med. I don’t think anyone else in the cabin even noticed it.

[Muddle238]

Lynx516 said:

I was on a flight this morning from Heathrow and as we climbed to altitude we climbed up towards another plane which was already at height.

As we got closer to it I realised it was at a constant bearing and I could now clearly read the wording on the side of the plane. So started to get a bit worried until we levelled off below it

I would estimate it was under 1km away. I thought they needed to keep 3+ miles apart? Is this normal or was this a bit closer than intended?

If separately vertically, then there's no minimum lateral separation required. The minimum vertical separation is 1,000ft.

It's quite normal to see other airliners flying past in the opposite direction along the same airway, but in the level above or below (1,000ft either above or below). Often at night we will flash our landing lights at each other.

[djc206]

Lynx516 said:

I was on a flight this morning from Heathrow and as we climbed to altitude we climbed up towards another plane which was already at height.

As we got closer to it I realised it was at a constant bearing and I could now clearly read the wording on the side of the plane. So started to get a bit worried until we levelled off below it

I would estimate it was under 1km away. I thought they needed to keep 3+ miles apart? Is this normal or was this a bit closer than intended?

At that level it’s 5nm or 1000ft. In the U.K. 3nm is only used in the London TMA.

Nothing to be worried about, it’s what ATC is for. Failing that TCAS.

[GliderRider]

If the pilots do any form of gliding, then airliner separations will be pretty tame for them.

Paragliders



Sailplanes


and then there's a 'birdstrike', paragliding-style

Edited by GliderRider on Wednesday 1st November 00:45

[Chuck328]

GliderRider said:

If the pilots do any form of gliding, then airliner separations will be pretty tame for them.

Paragliders Paragliders



Sailplanes


and then there's a 'birdstrike', paragliding-style

Now those are two fantastic videos. Particularly enjoyed the first,

But then lets talk about the closure speeds between paragliders meeting head on and airliners meeting head on...

( yes I'm being rather facetious but the point remains.)

[GliderRider]

Chuck328 said:

Now those are two fantastic videos. Particularly enjoyed the first,

But then lets talk about the closure speeds between paragliders meeting head on and airliners meeting head on...

( yes I'm being rather facetious but the point remains.)

Fortunately at the altitudes that paragliders and airliners are likely to share (below 10,000ft), then the airliner is limited by regulation to 250 knots indicated airspeed. Still a lot quicker than a paraglider, but not 500+ knots the airliner may cruise at altitude.

If you want airliners and high closing speeds, when Laker Airways went bust in February 1982, one of their DC-10 Skytrains was enroute to the USA. To avoid it being impounded there, the pilot was instructed to turn around and come back when in the Westbound transatlantic corridor. As I understand it, this caused some fraught moments for them, now face-to-face with what had been the following traffic.

[Condi]

GliderRider said:

Fortunately at the altitudes that paragliders and airliners are likely to share (below 10,000ft), then the airliner is limited by regulation to 250 knots indicated airspeed. Still a lot quicker than a paraglider, but not 500+ knots the airliner may cruise at altitude.

Military aircraft are not though, and a "small" aircraft doing 250kts or even 100kts is somewhat concerning if you're not sure they've seen you!

[Royal Jelly]

GliderRider said:

Fortunately at the altitudes that paragliders and airliners are likely to share (below 10,000ft), then the airliner is limited by regulation to 250 knots indicated airspeed. Still a lot quicker than a paraglider, but not 500+ knots the airliner may cruise at altitude..

Point of order, and FYI - airliners routinely fly faster than 250kts below 10,000ft; either at ATCs request for a particular speed, or them cancelling speed control, in which case we (normally) accelerate to cruising IAS. Only the USA has 250<10,000 which can’t be waived by ATC.

Great vids, by the way..

[GliderRider]

Royal Jelly said:

GliderRider said:

Fortunately at the altitudes that paragliders and airliners are likely to share (below 10,000ft), then the airliner is limited by regulation to 250 knots indicated airspeed. Still a lot quicker than a paraglider, but not 500+ knots the airliner may cruise at altitude..

Point of order, and FYI - airliners routinely fly faster than 250kts below 10,000ft; either at ATCs request for a particular speed, or them cancelling speed control, in which case we (normally) accelerate to cruising IAS. Only the USA has 250<10,000 which can’t be waived by ATC.

Great vids, by the way..

Thank you Royal Jelly for the clarification re speed & altitude and glad you liked the vids.

Good point Condi. I recall hang gliding down the valley between Crickhowell and Abergavenny once, and some time later, when on the ground, seeing the Nightbird Buccaneer going in the opposite direction somewhat lower and faster.

Edited by GliderRider on Monday 13th November 10:53