Reduce speed limits in Class E airspace now!

[Blip]

I submited this post in another thread regarding the RA north of BN and thought it might be worth while making it a separate topic of discussion.



The time available to make a visual sighting and then the time available to react to that sighting is directly proportional to TAS. The (in)ability to manoeuver around that traffic is proportional to TAS squared.

While we are forced to suffer Class E airspace, perhaps we should introduce new self imposed industry-wide speed limits.

If there is good reason to limit IAS to 250 kts below 10,000 ft, then there is good reason to limit it to 250 kts above 10,000 ft.

Where is the evidence to suggest that 250 kts is slow enough to adequately facilitate the concept of "See and avoid" anyway?

My personal opinion is that we should really be bringing the speed right back to Flap UP manoeuvering speed (220 kts) below 10,000 ft. That is what I have been doing when flying in to non-radar Class E airspace like ASP. I simply notify the tower before hand and give them the circuit area ETA with this lower speed taken into account.

Also here are some numbers to consider.

When comparing 300 kts to 250 kts:

300 kts is 20% faster.
300 kts increases radius of turn by 44% horizontally and I suspect vertically as well. (By vertically I mean the distance taken to change the vertical speed from say -2000 fpm to 0 fpm).

Time to descend from F180 to A100 is about 4 minutes. 20% of 4 minutes is 48 seconds.

So for the sake of saving less than one minute, we are significantly reducing our ability to successfully see and avoid.

Infact would these two factors have a multplying effect? When at 300 kts rather than 250 kts, you have 20% less time to see the traffic, and then once seen, you have 44% less ability to avoid it.

1.2 x 1.44 = 1.728 :confused:

Are there any mathematicians out there that can make sense of these numbers??

When comparing 250 kts with 220 kts:

250 kts is only 13% faster.
250 kts increases radius of turn by 29%.

I know most avoiance manoeuvering is done vertically rather than horizonally, especially when TCAS is involved, but I think my point is still valid.

So anyway my proposal is this:

While flying in Class E airspace:

When within radar coverage:
Limit IAS to 250 kts at ALL levels.

When outside radar coverage:
Limit IAS to 250 kts above 10,000 ft
Limit IAS to 220 kts below 10,000 ft.

I know 220 kts sounds rather slow (believe me when I did it for the first time, 220 kts at 10,000 ft really did feel slow and unusually quiet!), but don't forget the TAS is still around 255 kts (470 km/h)!!

[18-Wheeler]

250kts isn't fast enough for minimum clean speed in a heavy-ish 747, we need to go faster to climb properly. We'll often get a "No speed retrictions' climb below 10,000', and accelerate to 300kts (or more) to 10,000' then settle on the normal cruise climb which is usually between 320kts and 350kts.
For approach at max weight (Classic at least) We need at least 240kts clean.

[Blip]

18-Wheeler.

In the case of Heavy jet operation as you describe, would it really be a problem selecting Flap 1 or Flap 5 (or whatever it takes) for that relatively short period spent below 18,000 ft?


It increased drag would only cost a little extra fuel (a ton or so) ;)

EDIT: That should read: "The increased drag..."

350 kts compared to 250 kts.

40% faster
96% Increased radius of turn.

1.4 x 1.96 = 2.74 :ooh:

Perhaps we really need to rethink what is considered the acceptable norm.

Remember when we use to drive at 60 km/h (plus a bit) past those kids going to and from school? It's not the done thing anymore, and driving at 40 km/h for a short period hardly impacts on your day (unless you are going a little too fast and you get your picture taken).

The power of V squared is too often forgoten or underestimated!

[Capn Bloggs]

Blip,
You are correct. But I have a simpler solution. Get rid of Dick and his airspace. If you lose 1 minute per sector at over $100 per minute, multiplied by every time you and the rest of us do it, why should Dick and his mates get away with a scandalous waste of public/pax money (just one minute per sector would equate to millions per year!) just so he can fly willy nilly and not talk?

I really do not think that B747s using flap at FL180 just to help avoid a VFR bugsmasher who refuses to participate in the system is right or just.

[tobzalp]

If I remember correctly Class E is speed limited to 250K already except for military and aircraft whose min speed is above 250K or somesuch.

[Blip]

Just to reiterate:

"While we are forced to suffer Class E airspace..."

So actually I'm hopefull that this mitigating idea will only be required for a relatively short period of time.

tobzalp You'll find that the 250 kt limit only applies below 10,000 ft.

[tobzalp]

Blip the training material I delivered to ATCs stated that the speed restriction in ALL of E existed. I am on days off and I will recheck this one when I get back to work.

[18-Wheeler]

In the case of Heavy jet operation as you describe, would it really be a problem selecting Flap 1 or Flap 5 (or whatever it takes) for that relatively short period spent below 18,000 ft?


It increased drag would only cost a little extra fuel (a ton or so)

Yes, it'd be a problem, an unacceptable one.
We can't run the wing anti-ice without the leading edge flap all up, and we're speed limited to 275kts with flaps 1 and 255kts with flaps 5.
There's also the fuel consumption, which would add up to quitea lot of extra fuel burnt over a year, etc.

When we're heavy it takes over ten minutes at full climb power to get to 18,000', sometime a little more, and then we have to accelerate to cruise climb speed to be able to reduce to reduced thrust climb power. Keeping the engines (mainly Rollers, not GE's as it doesn't worry them) reduces the life of the engine a noticeable amount.

No good, sorry.

[skylane]

I would have to second Capt Bloggs. Solve the problem - get rid of Dick and his cronies.

[I'm gone!]

How about flying everywhere as close to the "Barbers Pole" as possable and minimize your time in the afore mentioned retched "E" airspace:}

Cheers,
I'm gone!

[Suffering Sucataash]

Blip,

Please don't take this personal, but that is one silly and dangerous way to think. You are obviously part of the "Slow is Responsible" club which is infecting the industry at this time. To go off on your own and fly non-standard profile OTCA is asking for trouble - now from the other high performance aircraft in the area - when I follow another aircraft into say ASP, I would expect you to do 250 kts below 10,000 ft or get out of my way if you intend flying min man.

:yuk: :}

[SM4 Pirate]

Airspace Speed restrictions only apply below A100.

See MATS Pages 9-3 and 9-4 table 9.1.1.1

9.1.1.3 Unless required for safety reasons, civil aircraft must not be cleared to operate at indicated airspeeds greater than those indicated in table 9.1.1.1 above, according to the airspace class.

Bottle of Rum

[Blip]

18 Wheeler.

What you say about wing anti-ice surprises me. Does that mean that wing anti-ice is not available during take-off and initial climb?

What is the minimum clean speed during a MTOW climb and a MLW descent for the B747 then? Could you not maintain whatever the minimum clean speed happens to be?

I certainly appreciate that a little extra fuel burnt on each flight can add up to many $millions in this industry! However...

Suffering Sucataash

I won't take it personally if you promise not to too. :)
I fail to see how being at 220 kts at 10,000 ft could be considered dangerous. It would be no more "non-standard" than if you were running late and decided to maintain 320 kts from Top of Descent to 10,000 ft instead of 300 kts. I would never know and probably wouldn't care what speed you chose to maintain. Just give me your ETA in the circuit and we (if OCTA) or the Tower (if flying in to ASP for example) will work something out based on that information.

And in any case, are you suggesting that the perceived increase in danger due to my modest reduction in speed would out-weigh the benifits that I described? I don't think so.

And if we all complied with these lower speeds, there wouldn't be this problem that you percieve.

To those detractors. Please look again at those numbers I quoted in my original post and try and appreciate what a profound negative effect speed has on your ability to firstly SEE and then secondly AVOID those un-announced VFR aircraft. Then picture what happens when you fail to avoid. :uhoh: That is what we are ultimately talking about here.

Remember too that 250 kts is a "Maximum Speed". It doesn't mean I have to fly at that speed. Just as a country road might have a speed limit of 100 km/h. If I am driving down that road at night and I know there are likely to be unannounced kangaroo traffic out there, I'll be ******ed if I'm gonna be doing 100 km/h. Again the power of V squared!

Now, with the aeronautical and human physiological knowledge that I have, plus the duty of care accepted by me for myself, my crew, my passengers, cargo, and the aircraft I'm strapped to, I feel almost obliged to slow it down.

It just seems to me that it is such a simple thing to do, yet could really contibute to us all getting through this (hopefully short term) airspace mis-management.

[DirectAnywhere]

Blip, if I can answer for 18-wheeler and also put in my two bob.

Wing anti-ice is not available for takeoff and initial climb. However, given that the aircraft has to be clean for takeoff anyway this is not a problem. It is generally only 3 or 4 mins until the aircraft is in a clean config and the anti-ice becomes available again. Wing Anti-ice on a jumbo is a bit of a misnomer. It's recommended as a deice system. With any flaps out - wing anti-ice (as it's called) is not available.

What you suggest is simply unacceptable on departure. Minimum clean speed on a climb for a MTOW Classic is 280 kts. with an econ climb speed of 340 kts. This 280 knot figure is the Final Takeoff Climb speed plus 20 kts required manoeuvring margin. If speed is limited to 250 kts the aircraft will require flap 1 with only a 10 knot margin between min manoeuvring and the climb speed limit - unacceptable. The problem gets worse if the speed limit is reduced even further. At flap 5 at MTOW the aircraft only has 15 knots between min manoeuvring and the flap lim speed. This is acceptable for transient acceleration but completely unacceptable for climb.

Also, manoeuvring load limts are reduced from +2.5g to -1.0g clean to 2.0g to 0g with flaps out. Again, not acceptable if turbulence is anticipated.

It's not such an issue on arrival with min manoeuvring speed of about 240 knots at MLW. However, the econ descent is still 290 kts so it's well below that.

Blip, please don't take this personally, it's worth asking the questions you've asked, but you seem to be lacking somewhat in the area of heavy jet operation expertise. Many other FIRs have NO speed control on departing aircraft for the reasons I've discussed and ATC in Australia will virtually always waive speed controls if you "REQUIRE min. 280 kts." I'd rather take extra track miles when heavy due to vectors to avoid other traffic than climb at 250 kts. Rather than adjust the aircraft to fit the system, let's make the system fit the aircraft. Surely a more logical process??

[18-Wheeler]

Agree 100% with DirectAnywhere, well said.

[404 Titan]

Blip

Have to agree with 18-Wheeler & DirectAnywhere. I use to fly the A340 and your idea isn’t an option for all the reasons stated. Also nowhere else in the world has it. This would make Australia different and the laughing stock of the world aviation community. As DirectAnywhere said “Rather than adjust the aircraft to fit the system, let's make the system fit the aircraft”.

[eh you! Pilot!]

Blip,

You are starting to follow down the same road as Dick Smith. Dick is trying to dable in an area in which he has [u]no[\u] expertise/ idea about. And the only reason we have to put up with him is because someone did not shut the door last time he left and he seems to have re-entered. Just like Dick, Blip, it pays to do some research into what u are going to say before you go ahead and make a fool of yourself as you have just done.............. A good phrase is "It is beter to appear stupid, than to open your mouth and remove all doubt". I suggest then that maybe you do some research and get some facts and figures before you leave all of us wondering whether you have a brain at all!!!!!!!!!!!

eyp

P.S Happy Easter to all!!!!!!!!

[Capt Claret]

eh you Pilot, why not just state your reasons for disagreeing with Blip and leave it at that, rather than trying to prove how superior you think you are, compared to him/her.

It's the personal attacks on people that are spoiling the wider enjoyment of PPRuNe, IMHO. :{

ps having just noticed your Easter greeting makes me wonder why you posted the message at all.... not too much christian goodwill to fellow man displayed. :uhoh:

[Blip]

:rolleyes:

O.K. I'll type this really slowly so that you don't miss it a fourth time. Please make sure you read it slowly too.

I am against the introduction of Class E airspace.

I am against the introduction of Class E airpace!

Class C airspace cannot be re-introduced fast enough.

Class C airspace cannot be re-introduced fast enough!

Have I made myself clear? Good.

And that is the reason why I posted in the first place. It is all too clear to me that rollback (if it is to happen) will take many months to achieve. It is also clear to me that I am virtually powerless to do anything about this.

Besides doing my bit for the cause by writing protesting letters to the Minister for Transport, to DS himself, and discussing the subject with family and friends who ask me for my opinion, I decided to post an idea here on PPRuNe that allows the pilot to regain some of the power back again. I introduced some ideas that obviously have not occured to most pilots here.

With the concept of "See and avoid" in mind (because that is what the crumbling cornerstone of Class E airspace is about), I dared to question the wisdom of flying at 250 kts IAS below 10,000 ft and "anything you like" above 10,000 ft while supposedly looking out for VFR traffic. Does anyone really believe that the average airline pilot can successfully apply Class E concepts at 300 kts IAS [350 kts (650 km/h) TAS @10,000 ft or or 400 kts (740 km/h) TAS @ FL180)??

And as Voices of Reason has pointed out in other threads, TCAS doesn't count!

So that is where the initial post was comming from.

Replies like "Fix the problem. Get rid of DS." contributed nothing to this discussion.

18-Wheeler said:

We can't run the wing anti-ice without the leading edge flap all up...

This statement surprised me because on the B737 you can operate the anti-ice with the flaps extended. That is why I queried it. I wanted to know more. And now I do.

Direct Anywhere.

The use of hot air from the pneumatic system to heat the leading edge of the wing is called the "Wing Anti-ice" system. That is what Boeing call it. A pilot wanting to use that system will say something like "Wing anti-ice on thanks." That is why I refered to it as "Wing Anti-ice." I also know that it is more efficient in both terms of keeping the wing free of ice ( by preventing the super-cooled water from simply running back from the heated leading edge and refreezing further back where the heating doesn't reach) and reducing fuel burn penalties by using "de-icing" technique. The de-icing technique involves allowing the ice to build up on the leading edge, then heating the leading edge just long enough for the first layer of ice to melt, allowing the airflow to blow the whole lot away. Turning the anti-ice off again and allows the ice to build up again, and the process is repeated.

Please tell me where the knowledge is lacking there.

All I am guilty of is not knowing the various manoeuvering speeds of a B747 and similar. Well surprise surprise I have never flown one so why should I know what they are. So now thanks to you I do know about that too. Great! Now I can appreciate that there might be some problems for the really heavy metal flying out there.

The great majority of domestic jet traffic in this country is B767 carrying close to min fuel, B737, A320 (coming soon), BAE 146 etc. that don't suffer the problem of high min manoeuvering speeds. Sure if you're flying a fully loaded B747, get your speed waiver.

404 Titan


Also nowhere else in the world has it. This would make Australia different and the laughing stock of the world aviation community.


Isn't that ironic. I thought the reason this class E airspace introduction was a joke was because we were mindlessly trying not to be different!

eyp

It's really easy to agree with the mob isn't it?
Comparing me with Dick Smith is so far off the mark it's laughable. For a start, I actually do listen to what others have to say. I can be persuaded to change my mind. In fact I have done that already when it comes to really heavy jet operations. Did you notice?

If you don't ask questions, how are you going to learn? Did you expect me to pay for an B747 endorsement so that I would already know the problems describled to me by 18-Wheeler and direct anywhere?


trying to dable in an area in which he has [u]no[\u] expertise/ idea about.


You're wrong there too. I do have an idea as to what I am talking about. I am out there flying the B737 through radar and non-radar Class E airspace, trying to do my best to avoid whacking the likes of you and taking us both down in a ball of flames before wiping out the poor soules that happen to be on the ground underneath us at the time.

From the sounds of it, you've gone through your whole career without questioning anything. Too scared to come up with an original idea or question established ones and express them for fear of ridicule. Thankfully we're not all like that.

If you actually believe that hackneyed smart-@rsed phrase of yours regarding opening your mouth, then you should heed your own advice!

To all.

The question was never answered. Who decided that any IAS above 10,000 ft and 250 kts IAS below 10,000 ft would allow us to successfully see and avoid unanounced VFR traffic? Just because ICAO make the rules doesn't mean it can't be questioned.

Where is their research and risk analysis?

Who knows, maybe they have a DS too.

<sigh>

[404 Titan]

Blip

Mate, no one including myself was having a go at you. We know your heart is in the right place regards to NAS or shall we say the lack of it. All we are trying to say here is that on departure for a heavy, 250 kts <10000ft isn’t a viable solution. We are confined to SOP’s and the limitations of our aircraft.

Regarding wing anti-ice, the term is sometimes misleading. In a lot of aircraft it is a de-icing device. It should only be switch on once ice is starting to form to prevent ice forming on areas that aren’t de-iced. While on the airbus we can our SOP’s state:

Use Of Wing Anti-icing

Wing anti-icing should be used as a de-icing system after an appreciable amount of ice has formed or after leaving the icing zone and before extending flaps. It should not normally be used as an anti-ice system i.e., turned on continuously in icing conditions, due to performance penalties and runback ice formations. Operation of the wing anti-ice system with flaps extended MAY not be recommended. Refer to aircraft Operations Manual.

Ice accumulation on the flight deck windshield frames, windshield centre post, windshield wiper post, or side windows can be used as an indication that airframe icing conditions exist.

This statement surprised me because on the B737 you can operate the anti-ice with the flaps extended.
Don’t know about the B737, but on the A340/330, the wing anti-ice is inop while slats are extended. There is a very prominent caution in our Supplementary Procedure, Ice and Rain section warning us to avoid flight in icing conditions with the slats extended. This is because it would leave us very vulnerable to ice formation on the slats possibly then preventing us from retracting them and creating multiple problems, which could lead to an emergency.

[DirectAnywhere]

Geeze Blip, tetchy, tetchy!!

Firstly, apologies if I insulted you or hurt your feelings. That was not my intention.

From my first post:Wing Anti-ice on a jumbo is a bit of a misnomer. It's recommended as a deice system. With any flaps out - wing anti-ice (as it's called)
I was never questioning your knowledge of the name of the system, or knowledge of what it does. I know it's called anti-ice and I know what it does too, OK?

My questioning of your heavy, and I emphasise heavy, jet experience was related to your lack of awareness of the operating limitations that are there for heavy weight jumbos. It was not intended to belittle or insult you. You asked the right questions and I hope the answers help put things in perspective for you.

I still have a problem with forcing aircraft that have been designed to fly under a certain regime of speeds and profiles to operate another way simply as a result of poor airspace design. Also, for the aircraft I fly, it's totally impractical. I see your point, and appreciate what you're getting at, but I think it opens a whole new can of worms by forcing aircraft to operate off profile in airspace that's substantially lacking.

In my belief, it simply puts another hole in the swiss cheese.

Cheers.;)