Most popular cruising altitudes

[abgd]

I'm running a small poll to find which cruising altitudes people tend to choose the most often.

Discussion is fine, but please try not to mention specific numbers to avoid biasing later respondents.

Many thanks!

[Fareastdriver]

Any 1,000s of feet plus 200.

[JTobias]

Hi,

It's been a long day, and maybe I've missed something, but

a) I don't understand the question described on the poll. Are those numbers representative of hundreds of feet ??
b) any reason they're not in numeric order
c) given that it's VFR flight, I presume you're referring to height AGL rather than altitude

Joel :ok:

[before landing check list]

I think it would depend a lot on mission, equipment, terrain, weather, aircraft, distance to fly etc...

[Harry the Hun]

Below 50 feet AGL. Unfortunately pax have a tendecy to feel uncomfortable in that regime. Have no sense for fun, them bastards. :-)

[SilsoeSid]

As JT, I also clearly missed something there.
(Ignore one of the x600's, I wanted see what was next.....nothing!)

Anyway, my answer to 'the question', with a few assumptions, would mainly depend on which way I was going.

[homonculus]

Is this another trick CAA ATPL question:ok:

I don't understand it. I presume you can't answer anything except whole thousands of feet so I couldn't answer

:mad:

[2Sticks]

Well I just c*cked that one up - I took the chance that some other option would pop up if you chose one of the options but it doesn't. I give up. :ugh:
2S

[JTobias]

Thanks Silsoe,

I thought I was going a bit daft.......
I see he's not yet answered :confused:

Joel :ok:

[before landing check list]

Wondering why x000 is there.

[bast0n]

Good Man, Hun

Below 50 feet AGL.

Perfect - and you can frighten the chickens. My sisters, (her chickens you deviants) spent weeks up in the Wisteria after a quite low pass.

Happy days..................:O

[Jet Ranger]

...after the 212 low pass (below 50'), no eggs in a next one month!:E:}

JR

[Redland]

Ok may be I am missing the joke but it seems quite strait forward. Answered and will not mention my answer but, I take it most people cruise at x thousands of feet on the dot on a QNH. I was always taught to go for a few hundred feet above or below say 2000ft and therefore an extra margin of safety????

Is this not what is being asked?

[abgd]

I'm sorry if I inadvertently broke any of the rules on PPRUNE - I hadn't realised that permission was required to post a poll and wasn't (and remain uncertain) who to ask for permission. If the moderator who pulled the link would like to PM me, I'd be happy to discuss its purpose.

In outline yes, I am interested to see whether people are clustering around particular altitudes or using the airspace more fully. It's just for personal curiosity - I'm not affiliated to an university or any other institution.

[Madbob]

Okay, I'll bite.

The question seems fair to me and what abgd is asking is whether we all tootle off into the wide blue yonder cruising along at 2,000 ft on the regional QNH as we we all probably taught eons ago when doing our (VFR only) PPL navex's.

If so the collision hazard is going to be higher than if we made better use of the airspace available. The other "popular" level to cruise at I suppose is just beneath the local cloudbase. But this again could create a higher risk if we all scud along at 200 ft below the cloud base.

Personally, I think it best to follow the quadrantal rule and if too low for this to be practical, to fly at an "odd" level say 1,800 ft rather than 2,000 ft just to avoid all the others out there that a. might be tooling along at 2,000 ft (+/- 100 ft!) and b. not keeping a good look-out.

I know that this is not a guarantee of avoiding a mid-air, but psychologically I think I am mitigating the risk, and you can't ignore all the military types, gliders, microlights and balloons that are out there too, which all seem to have their own ideas.:}

Just my 2c.

MB

[heli1]

Since everybody seems to be flying at "odd" altitudes I think I'll fly spot on in future. It sounds safer!

[ShyTorque]

My 2c is to ask all pilots flying aircraft with a Transponder Mode C / Alt: Please use Mode C, not just Mode A.

Those of us operating aircraft with TCAS/TAS will use it to avoid you; we will know you are there and at what altitude. We can then use that information to help deconflict, well before you see us. If you don't use Mode C it makes the system much less effective.

[topendtorque]

abgd (http://www.pprune.org/members/368834-abgd) I didn't see your poll, but get the drift. There are a couple of things that need to be remembered when flying helicopters, neither of which are in your syllabus.

1. Fixed wings always fly faster and neither they nor your rotary colleagues can see you if you are just below their horizon. Experiment with this and use radio advisory carefully..

So take care in selecting a cruise altitude, especially as it seems most here are selecting their own away from conformity, Any that are tracking anywhere near your position either above you from your aft positions or perhaps below you at your forward positions are extremely dangerous.

2. When you fly out bush with its vast distances between settlements of any sort, let alone another drop of fuel away from the great populations of fuel pumps, rampant air traffic controllers and everyone else there is only one rule.

Always shop around for and find the best tailwind or at least the least headwind. With GPS nowadays that is easy, not so easy before but a very godlike discipline.

cheers tet

[ShyTorque]

Fixed wing always fly faster? Not here they don't. If you're talking Robinson maybe but in UK many helicopters fly faster than light FW.

[topendtorque]

Yes Shy,
but look at it this way. Not everyone can skite about bird strikes on the trailing edge of their sync elevator, as a late friend of mine, Geoff Brown, used to quip whilst he tooled past in the RAAF rescue S 76.
tet

[ShyTorque]

More than once I've been directed to "make best speed" in the approach pattern then been told to slow down on the ILS because I was catching the airliner ahead. ;)

[pilot and apprentice]

As was said before, and it is still true, the poll supposes (or fails to ask) a lot.

There are, depending on location, many regulations that will limit what altitudes are 'available', there are terrain issues, winds, and on it goes.

I will add my +1 to the comments that good situational awareness that uses all assets (ATC, TCAS/TCAD, radio in and out, lookout, airspace knowledge) is necessary for traffic avoidance. Cruise height choice is just one link in a long chain.

Sometimes it's just a pleasure to do something different when the opportunity presents itself. On a dreary, grey day file and get up on top to see the sun just because you can. Easier in a jet but there are days when even us rotary guys can do it. Or if the daily grind is IFR, then do a min VFR height transit and pull out a paper map.

It is amazing how much pleasure the job used to have, that can be refound with a little effort and an open mind.

[Senior Pilot]

Since it seems there is some confusion in what is being asked here, and PPRuNe has a limit on what can be asked in a poll question, the OP is seeking a response to establish by what difference you avoid (or don't avoid) cruising at a specific height on a clear VFR flight.

Not what actual height you choose to fly.
Not which direction you are flying.
Not what is the terrain clearance.

Just by how many 100's of feet you may choose to avoid a semi-circular or quadrantal cruise altitude, to reduce the risk of meeting someone else at the same height.

The OP requested a random order to avoid the donkey vote: I think! Since a poll keeps bumping the thread to the top of the forum with every vote I have put a limit and the poll will close next Wednesday,

[pilot and apprentice]

SP, thanks for the clarification. But still, the OP seems lacking if real information is desired.

In the jurisdictions where I have flown, a VFR quadrantal is not an even 1000', that would be an IFR altitude. The 500' offset up from that is the preferred (prescribed) altitude. I know, telling you what you already know, but stating it for the sake of the other readers. I do not know what the current European view on these things is.

My advice about SA was to address the implication that a poll like this could establish what a good deconfliction offset is.

[SilsoeSid]

Being one that would generally follow the quadrantals even below transition altitude and therefore 'long transit' at 1000, 1500, 2000, 2500 or 3,000 depending on heading and/or terrain, this thread is quite an eye opener, (especially as i thought that we all generally followed the same thought, with a 500' seperation in mind).

It seems that I might as well pick a height for the best view for the day, switch all the lights on and hope peeled eyes and the TCAD show where everyone else is :eek:

Just because you don't have to doesn't mean you shouldn't!

[pilot and apprentice]

I concur SS, I seemed to remember the rules over there were slightly different but the idea is the same. The guidance was put in place for a reason: all regulations were written in blood.

Stay safe out there

[Gomer Pylot]

I didn't vote. I have no real preference. I find the best groundspeed and fly there. I don't really care how far off the prescribed altitude it is, nor the direction. OTOH, if I do go above 3000' AGL, regulations do prescribe the altitude I'm to fly, and I maintain that. Below 3000' AGL, it's entirely random for me. Depends on the winds, the height of the buzzards and hawks, and how I feel at the moment.

[heliski22]

Did I miss or misunderstand something?

If my planned or nominated altitude was to be 2000ft, the poll doesn't allow me to vote for zero (000ft) deviation because I flew at that altitude - is that right?

Curiously yours...

22

[Vortex what...ouch!]

1500ft plus, why would you fly lower? If it all goes to rat****, you need a few seconds to figure it out.

[copterdude]

I typically fly 500ft agl

M.

[nigelh]

Between 500 and 1000 ft. Agl depending on winds .

[topendtorque]

Did I miss or misunderstand something?

If my planned or nominated altitude was to be 2000ft, the poll doesn't allow me to vote for zero (000ft) deviation because I flew at that altitude - is that right?I'm with you, in CTA which is seldom, I fly the numbers, that way I can find other traffic in front of me at the correct height, by drifting down a tad I'll have them instantly on the horizon, if others are given me as traffic from behind me, I'll just drift up a tad fifty is all it takes for them to see me, then back on line.

But as before with x country wind is everything. Into wind, usually be on the deck keep straight - read a book and pop up a couple of hours or so later at the ETA of being able to ID a known position, sometimes you will find a pressure wave down low which needs avoiding, and downwind in these parts it is either 300 to 500 agl or 1700 to 2200 agl is quite usual where a small pressure wave can be found.

Though there is one area not far from here where very strong Sou Eaters can be found during winter time at between 5000 and 6500 at 50 to 70 knots and about 200 x 150 nautical miles in extent. They have brought plenty of F/W undone. That sort of local knowledge was always passed on from the local FSU when we had them, now people find out the hard way because it usually isn't on the forecast.
tet

[ShyTorque]

Being one that would generally follow the quadrantals even below transition altitude and therefore 'long transit' at 1000, 1500, 2000, 2500 or 3,000 depending on heading and/or terrain, this thread is quite an eye opener, (especially as i thought that we all generally followed the same thought, with a 500' seperation in mind).

The Quadrantal rule doesn't apply below 3,000 feet so you shouldn't be too surprised if you don't find anyone else complying with it. Many light fixed wing (SEP) pilots will fly at 2,000 feet simply because that's what they're often taught to do, irrespective of track. Worth bearing in mind that you fly on an AOC where the 1,000 foot and 500 foot rules don't apply - but other pilots will have different priorities when it comes to choosing a cruise altitude.

[SilsoeSid]

The Quadrantal rule doesn't apply below 3,000 feet so you shouldn't be too surprised if you don't find anyone else complying with it.

As its only recommended for VFR flights above 3,000ft anyway, and it seems that things like transponders and contrasting paint schemes are unjustified expenses out there, I'm never really surprised with what pops up ! :ooh::eek:

It was just something to hang my hat on. Judging by some of the posts here, I shall go and refresh my low level engine off skills ;)

[topendtorque]

It was just something to hang my hat on. Judging by some of the posts here, I shall go and refresh my low level engine off skills http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/wink2.gif

Yes you should Sid, you may discover how refreshingly simple it is to do one even from thirty feet when running into a thirty knot headwind. That's why I always try for at least 300 feet when I am running downwind, never turn downwind below 40kts indicated etc etc.etc.

[Nigel Osborn]

Tet,

You wrote "late Geoff Brown", am I right in thinking he is no longer with us? If so please pm me.
Thx.

[SilsoeSid]

Tet, I said refresh, not learn, thanks :ok:

[Rotorgoat8]

I was always told by my heli mentors that anything over 500 AGL was nose-bleed territory for chopper jocks.

[ShyTorque]

I was always told by my heli mentors that anything over 500 AGL was nose-bleed territory for chopper jocks.

For a long time this winter it was IMC and in the icing layer, too!

[topendtorque]

Tet, I said refresh, not learn, thanks http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/thumbs.gifNo worries Sid, being ANZAC day thought I'd just lay one on for effect - barely raised the dust, as I might have known with you, regards.

I was always told by my heli mentors that anything over 500 AGL was nose-bleed territory for chopper jocks. This is true and you may have noticed that Vertical Freedom's photographs show a tendency to be very close to the ground all the time. Now I'm only guessing, but it's probably the same phobia - being too high above ground in that country could sure cause real bad nose bleeds.

For a long time this winter it was IMC and in the icing layer, too! Well you mob did have a drought over there - and then with a bout of silliness someone went and invited Flannery into the country who foretold - doom, gloom, more drought. Surprise, surprise you nearly all got washed away, ice snow the whole nine yards.You'd be far better having everyone turn their pink ear to James Dellingpole.

cheers tet

[handysnaks]

I shall go and refresh my low level engine off skills :suspect:



;)

[abgd]

OK... I'm sorry for the delay in posting results. Sometimes life gets busy. I quite agree with the frustration some people feel when confronted with such an odd question. However, I did have a halfway sensible rationale behind it. It relates to a trick many pilots use to reduce the risk of a mid-air collision, which is to fly at a 'random' altitude, the assumption being that most other pilots will be flying at 'round' altitudes such as 2000 feet, or 1500 feet.

There's a children's game where if you ask someone to think of a vegetable under time pressure, almost everybody thinks of a carrot. If you ask people to think of a flower, most people think of a rose. But what if you ask people to think of a random number - for example a random altitude?

There's unfortunately surprisingly little research on this, though what little I've seen tends to suggest that we also have prototypical 'random' numbers that we prefer. And intuitively 2300 feet somehow seems more random than 2000 feet or 2500 feet, doesn't it? It does to me, though of course I know that 'randomness' occurs in the process of selecting an altitude, not in the individual result.

In my polls, I randomised the order of presentation of the altitudes to try and avoid any bias due to page position, and posted different versions of the same quizes on several fora. I'm not particularly serious about this question and I'm sure I could have carried out the questionnaires more rigorously, but it's a start. And the results were significant, both in practical and statistical terms.

This first graph shows the altitudes pilots select if they consciously choose to pick a 'random' cruising altitude.

"Many pilots try to pick 'random' cruising altitudes in order to reduce the risk of mid-air collisions.

Ignoring all other considerations, if you were trying to use this strategy on a VFR flight, which altitude would you be most likely to pick?"

http://farm8.staticflickr.com/7348/9110412361_939b91f686_z.jpg

182 responses - risk of collision 150% greater than the theoretical optimum.

The result is clearly biased towards '3' and '7', which I had predicted, though '2' and '8' surprised me in their popularity. '2' was only really popular on one forum - and this one, which made me wonder whether someone was possibly trying to fiddle the results. However '3' was popular on every forum where I posted the quiz, whatever order the options were presented in.

Incidentally, and without meaning to be churlish, I did not count results from the poll that got posted on this page for a number of reasons (missing entries, change in question, ability to see and discuss results prior to their final compilation). However, thanks to everyone who filled in both this poll and the one that I initially posted. I am also grateful to the mod who tried to recreate the poll on this forum - PPRUNE initially pulled it due to a breach of terms (no links to external polls) of which I was unaware, and have no quarrel with - their site, their rules.

However, not every pilot knows the 'trick'. What altitudes do people actually fly at? The best way to do this would be to sit watching mode-C returns over Wales or Scotland - somewhere where people choose altitudes on the basis of preference rather than compulsion - we often don't have much choice. However, that's not something I currently have the time to do so I posted a separate poll elsewhere asking people to pick an altitude.

"It's a fine day for a VFR flight, and you can choose to fly at whatever level you want. Pick your favourite cruising altitude, and select the whole number of hundreds-of-feet on the poll below. Thanks!"

http://farm4.staticflickr.com/3773/9110412241_c519f866fc_z.jpg

112 responses altogether. Risk of collision 152% greater than the theoretical optimum.

The result - to my eye - shows a mix of 'random' cruising altitudes, with the big round numbers of thousands of feet, or five-hundred foot increments. Perhaps surprisingly here, people have tended towards lower numbers rather than higher numbers. i.e. x200 feet seems much more popular than x800 feet.

~~~~

Working from the reasoning that the risk of collision increases with the square of traffic density, it's possible to calculate a theoretical optimum if traffic were evenly spread throughout ten possible cruising levels offered as options... which begs the question 'why only ten options'. It's a good question to which I don't have a ready answer, except to point out that most of us are limited in our altitude-keeping ability. I realistically keep within about +/- 100 feet most of the time. Perhaps some of you do much better. However, there's no advantage to aiming to fly at 10 foot increments if we're straying so far from our allotted altitude. Really I picked hundreds of feet simply because that's how we normally report our altitude. I never heard anybody say they were currently at '1775 feet'.

Whenever traffic is spread unevenly, risk of collision increases above the optimum. e.g. if pilots fly at whole 1000s of feet, the risk is 10 times greater than the optimum (assuming 100 foot increments).

Someone on another forum quite reasonably pointed out that there are advantages to flying according to quadrantal rules - though under EASA I understand that we're moving towards the semicircular rules in line with the rest of the world. If we restricted ourselves to 500 foot increments, our theoretical risk of collision would be 5 times greater than the 'optimal' risk. Of course it's mitigated by the fact that we are now less likely to meet another pilot on a reciprocal heading (though closing speeds may remain quite substantial). Does this mitigation outweigh the relatively large risk increase by confining ourselves to just two levels per 1000 feet? Quite possibly. I don't know.

Perhaps the ideal would be to combine the two techniques:

Take the last digit of the day of the month in your birthday - e.g. 16 february. Add or subtract 5 - whichever leaves you with a positive, single digit answer. You now have two single digits, 1 and 6. Fly quadrantal rules, but instead of flying at x000 feet, fly at x100 feet. Instead of flying at x500 feet, fly at x600 feet. If everybody did this you would be relatively unlikely to meet anybody going the opposite direction, and you would also spread out the traffic almost evenly over the available airspace.

~~~~~

Another point is simply that en-route mid-air collisions are vanishingly rare and not really something to worry about unduly.

So arguably fairly pointless, but I had fun anyway. Thanks to everyone who filled in the polls.