A retired coworker's husband was a Capt for UAL (European routes) and he died of cancer. I am pretty sure it was brain cancer. RIP JVB.

Altitudes above 28,000 used to have 2,000' separation, rather than 1,000' separation. With the introduction of RVSM (reduced vertical separation minima) upper flight levels were reduced to 1,000' separation. There are specific aircraft requirements attached.

Generally east altitudes are odd, west are even, but it's possible to be assigned a "wrong way" altitude, as well.

Aircraft operating in RVSM today are usually under radar control, except for oceanic areas, and are equipped with TCAS (traffic collision avoidance system), in which transponder devices on board each aircraft "talk" to each other. When the flight path of two aircraft could create a collision hazard, an alert is issued to each, and at a certain point, vertical speed directions are issued as a "resolution advisory" to prevent a collision.

A system called ADS-B is also being implemented and will be required on all aircraft by 2020, allowing aircraft globally to see each other on a display, to aid in collision avoidance.

In the case of the original poster, both aircraft were in Class A RVSM airspace, in radar contact with a controller, aware of each other via TCAS, and most likely were also in visual contact.

Navigation has become so precise today that two aircraft 5,000 miles apart can fly toward each other along a track, routing, or airway, and pass exactly over one another. Because of this, many routings around the world allow or employ the use of SLOP, or strategic lateral offset procedure; the crew will offset their course 1-2 miles and parallel their course. SLOP is randomly selected by the crew, with the idea being more separation for safety and for wake turbulence avoidance. In the most congested airspace on the planet, the north atlantic tracks and high level airspace, SLOP is now done in .1 nautical mile increments.

It's very hard to tell visually at high altitude whether an approaching aircraft is at the same altitude, or above or below, until close to that aircraft. An aircraft within a thousand feet may appear to a passenger to be at the same flight level.

In the US airspace, altitudes below 18,000 are referred to as altitudes, while above that are referred to as flight levels. 36,000' is Flight Level 360, or simply FL360.

Altitudes are limited by performance, weight, and temperature aloft. Transport category aircraft will have an optimum altitude for a given weight and temperature aloft, at which the aircraft will cruise most efficiently. Cruise altitudes are also selected based on winds aloft, weather, and turbulence. Altitudes above or below optimum suffer in performance, and fuel consumption. At high altitudes, not only is stall speed a concern, but an upper speed called mach buffet speed; the space between them narrows with a climb in altitude, and narrows appreciably above the optimum altitude.

So you got your East/West altitude explained, how about North/South flight? Or Diagonals such as NW/SE ?

quote:

Originally posted by OKCGene:
So you got your East/West altitude explained, how about North/South flight? Or Diagonals such as NW/SE ?

000-179 Degrees is East

180-359 Degrees is West

It goes by magnetic course: anything 000 degrees through 179 is east, or an odd altitude, and anything on a magnetic heading of 180 degrees through 359 degrees is to fly an even altitude.

This called the hemispheric rule.

--edit, as noted above (post seems to have disappeared by erjpilot); it's course, not heading. Course is the track over the ground. Heading can be substantially different. An aircraft flying a track of 002 degrees with a strong westerly wind may have a heading of 340 degrees, for example, but still fly an odd altitude because the track or course is 002.

You guys are all over it, so I bowed out.

quote:

Originally posted by erj_pilot:
You guys are all over it, so I bowed out.

Your initial post was correct; mine was in error. I said "heading," but revised it to clarify.

quote:

Originally posted by sns3guppy:

quote:

Originally posted by erj_pilot:
You guys are all over it, so I bowed out.

Your initial post was correct; mine was in error. I said "heading," but revised it to clarify.

And I went to post a correction to that and you had already caught it...

All great answers gang. Once you reach FL410, RVSM airspace stops, required separation goes back to 2,000 foot intervals above that. We separated traffic at FL600 and above by 5,000 feet, class E airspace again.

V-Tail, thanks for the compliment!

quote:

Originally posted by coloradohunter44:

All great answers gang. Once you reach FL410, RVSM airspace stops, required separation goes back to 2,000 foot intervals above that. We separated traffic at FL600 and above by 5,000 feet, class E airspace again.

Now I'm curious -- something I never thought about: Is VFR permitted in the Class E above FL600, and if so, are the VFR altitudes 500' higher than the corresponding IFR altitudes? Are altimeters in this airspace set to standard pressure (29.92), or to locally reported barometric pressure? Do we still use flight levels up there, or are we back to MSL?

I need to know this stuff in case I ever fly in that Class E airspace.

Welllll, we only ever had SR71, and U-2’s above FL600. They remained on 29.92, but we had to use 5,000 foot separation. No one ever canceled and went VFR that I’m aware of. We had to get the code book out if we had two of them to look up their altitudes, they just checked in “above FL 600”. And only ever had to do that once in all my years. I’m not sure if much has changed since I retired, with satellites, only a few research birds were left flying last I knew.

quote:

Originally posted by sourdough44:
... operating in close proximity to an A380 ‘Super’.

Even though I am not a pilot, these aviation threads are fascinating and I always learn something.

Speaking of the A380, earlier this summer I headed over to an industrial park just outside the perimeter of O'Hare to get a look at the one British Airways uses on its LHR-ORD route to get a look at it. That plane is huge.

Here's the story of the incident that ended VFR at high flight levels.

quote:

Originally posted by coloradohunter44:
Welllll, we only ever had SR71, and U-2’s above FL600. They remained on 29.92, but we had to use 5,000 foot separation. No one ever canceled and went VFR that I’m aware of. We had to get the code book out if we had two of them to look up their altitudes, they just checked in “above FL 600”. And only ever had to do that once in all my years. I’m not sure if much has changed since I retired, with satellites, only a few research birds were left flying last I knew.

U2s do fly VFR above FL 600 on occasion OCONUS.

One fun thing about aviation, for every rule there’s an exception!

quote:

Originally posted by coloradohunter44:
Welllll, we only ever had SR71, and U-2’s above FL600. They remained on 29.92, but we had to use 5,000 foot separation. No one ever canceled and went VFR that I’m aware of. We had to get the code book out if we had two of them to look up their altitudes, they just checked in “above FL 600”. And only ever had to do that once in all my years. I’m not sure if much has changed since I retired, with satellites, only a few research birds were left flying last I knew.

The U-2 Dragonlady is still around, although you don't see them often.

The highest I ever got in the F-14B was FL530, because one of the pilots wanted to get his 50K check in the block before the airframe went away (over international waters) - I wasn't excited but he worn me down and I said oh well, if you'll finally shut up about it, lets do it.

Not the smartest thing we did since we didn't have pressure suits, but thankfully the GE110 motored Tomcats could still get up there pretty quickly and we didn't do much more than hit 50k, look around and immediately start coming back down.

quote:

Originally posted by RHINOWSO:
The highest I ever got in the F-14B was FL530...

I can't imagine. Took my Harrier up to FL440 once - once. Extremely uncomfortable; regulator blowing O2 for all it's worth and sounding like Mickey Mouse on the radio. And the plane just wallowing, like balancing the plane on the head of a pin.

Pinnacle 3701 bit the dust when it went up to FL410. Most of us assumed the crew did it so they could boast about being "Eight Miles High..."

It's not the altitude that got Pinnacle, but the operation. Flying above optimum requires additional thrust and can quickly approach maximum power settings. Temperatures and speeds must still be respected.

I have spent a lot of time at FL410 and occasionally above. I've spent a lot of time at FL410 in turboprops, in fact. There's nothing magical about the altitude so far as aircraft go.

I've flown aircraft that had higher altitudes of which they were capable and certified and designed, but that were restricted due to oxygen masks, and other reasons. The aircraft may be able to go higher, for example, but the model of mask installed isn't.

Physiologically, altitude effects onsset much more rapidly in the event of pressure loss, at FL410 or higher. Pressurized aircraft, particularly large pressurized aircraft are operating at their maximum differential pressure at those altitudes in most cases, and most would be surprised just what effect that has on a big, aluminum structure, which blows up like a balloon. The fuselage increases dimensionally, with considerable repetitive stresses on the airframe. There are many, myself inlcluded, who prefer not to push old airplanes too hard.

I was at 410 a few years ago when aircraft up ahead, substantially higher, reported descending to an 60,000.' I queried the controller about type. It was two B2's.

The immediate problem with pressure loss at high altitudes isn't just the sharply reduced TUC or time of useful consciousness (which can be as little as 15 seconds at FL410). Go high enough and pressurized flight suits are required to protect against the effects of reduced vapor pressure in the blood stream, should a pressure loss occur.

I've had two in flight rapid depressurization events, one explosive (one front cockpit window blew out. It can be disorienting, in addition to other hazards. It can get cold, loud, things fly around, it literally takes your breath away, ears and teeth hurt, it can blow out sinuses and rupture ear drums, even cause dental problems (had that once, too, due to an air inclusion under a filling that vented into the jaw. I felt it blow. I've never felt anything like that before).

A pilot must be able to don and seal and use 100% oxygen, delivered under pressure without dilution, in five seconds. Passenger oxygen is neither delivered under pressure, nor does the mask seal, and it's diluted, not 100%, and very short in duration

quote:

Originally posted by mojojojo:

quote:

Originally posted by RHINOWSO:
The highest I ever got in the F-14B was FL530...

I can't imagine. Took my Harrier up to FL440 once - once. Extremely uncomfortable; regulator blowing O2 for all it's worth and sounding like Mickey Mouse on the radio. And the plane just wallowing, like balancing the plane on the head of a pin.

We were supposed to fight a French Rafale that day in the Arabian Sea off the coast of Pakistan, but the Frenchman didn't show up, so we had nothing to do for the 1+15 w/20,000 of gas.

As the squadron was transitioning from the F-14B to the FA-18F, so lots of the younger pilots wanted to get checks in the block (speed, altitude (high and low), etc).

I forget how fast we were going, but it had to be in the 1.4IMN range (not the fastest I've been) and the turn circle was the size of Texas. The plane was feeling pretty good (performance-wise) to me - the surging ECS (Environmental Control System) was the worst part of it - well that and the thought of what a rapid decompression would feel like.

I was very glad to see the altimeter pass 50,000' on the way down... I have a photo of the altimeter but think it's on CD somewhere, as I can't find it on my computer right now.

The only regret I have is not going for the 2.0IMN check; 1.85IMN was the fastest I made it (level at 40K). NATOPS limited us to 1.88IMN for skin heating, but what's .12IMN among friends? I'm sure if we had unloaded for 15 seconds we would have popped right through it.

quote:

Originally posted by RHINOWSO:
I was very glad to see the altimeter pass 50,000' on the way down...

We usually did our “cross country” flights in the mid to upper 20’s where the plane handled much better. Leave that 50k stuff to those Eagle, Spirit, Lightning, etc. drivers.

We were WAY more comfortable operating at 200’ and below than at altitudes above 30k.