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-   -   At what speed does VFR become too difficult? (https://www.pprune.org/private-flying/308366-what-speed-does-vfr-become-too-difficult.html)

chevvron 13th January 2008 18:06

I once took John Farley in G-VTOL from Dunsfold to Bedford on radar; it took about 7 min takeoff to touchdown; on another occasion Duncan Simpson was taking a Hawk to Hatfield (from Dunsfold again) and asked (husky voiced) 'is it OK to do 350 here (Woodley below controlled airspace) or should I slow down'!!

Contacttower 13th January 2008 18:07


Come on, chaps, just calm down!

I couldn't agree more Tim (and FWIW I thought your 'remember to say unable' thread was a very good idea).

One is sometimes just left feeling on PPRuNe you simply shouldn't have posted anything in the first place. :ugh:

llanfairpg 13th January 2008 18:12

But boys and girls dont take it too seriously, life is only another game

charliegolf 13th January 2008 18:14


At what speed does VFR become too difficult?
When the aeroplane is doing X KIAS, and your brain is doing X-10 KIAS. The end will be nigh.

CG

BEagle 13th January 2008 18:26

"Well whatever you call it when ATC advise you are identified, give you a squawk, steer you away from traffic, descend you and steer you for the centreline."

:hmm:

My 'Walter Mitty' caution has just lit up.....

Kid with a scanner?

dublinpilot 13th January 2008 18:31


Good idea, with the radar controller the star perhaps, with TCAS and transponders as support
But isn't that the whole point of see and avoid being the last line of defence outside controlled airspace? Aircraft outside controlled airspace are not required to have transponders, nor TCAS, many don't even have electrical systems.

I know you'll say but what about primiary radar.....I'm getting a radar advisory service, but as I understand it many types don't paint very well on primary radar. Primiary radar also gives no altitude indication. Hence the need to have see and avoid, which has only got a chance if the speeds aren't too great, which is why we have a speed limit.

dp

S-Works 13th January 2008 18:31


Ah, see your off the floor Bose.

Thanks for your interest Bose but might be best if you save your quips for the good slagging you keep geting on the IMC rating thread.

To be fair every-time you post I end up on the floor laughing. I may get slagged off but at least I am consistent.....

It does amuse me though how you sink to personal abuse when unable to come back with wit when a bit of humour is aimed at you.

So you going to answer the question then!

llanfairpg 13th January 2008 18:32


My 'Walter Mitty' caution has just lit up.....
Are you sure that wasnt about 40 years ago at Cranfield?

llanfairpg 13th January 2008 18:40


To be fair every-time you post I end up on the floor laughing. I may get slagged off but at least I am consistent.....

It does amuse me though how you sink to personal abuse when unable to come back with wit when a bit of humour is aimed at you
Happy to help--but see if you can stop laughing at yourself and stick to the thread.

BEagle 13th January 2008 19:04

Master Caution has now become a Master Warning.......

BackPacker 13th January 2008 19:08

Oh man, I was out flying this afternoon (training aerobatics, 2000' hard deck, 2500' lower limit and BKN033 - good practice) and missed this slugfest. Three pages in, what, four-five hours? Fortunately it's all recorded for posterity.

Anyway,


Isn't the whole purpose of the 250kt speed limit to allow see and avoid some chance of working?
Don't know if that's exactly true, but I do remember seeing somewhere that airline cockpit windows have to withstand a bird strike (of a certain size/weight bird) up to 250 knots.

llanfairpg 13th January 2008 19:13


Master Caution has now become a Master Warning.....
Only Master Bates left for you now--enjoy

frontlefthamster 13th January 2008 19:14

250 below 10 is priincipally about see and avoid, though just why is lost in the mists of time. There are similar certification issues, which are convenient for manufacturers who don't want to fit hugely expensive windows. :8

In answer to the original question, why does it matter? Just change to IFR. :ok:

BEagle 13th January 2008 19:23

On 16 Dec 1960, a United Airlines DC-8 and a TWA Super Constellation collided in midair over Brooklyn, N.Y., killing all 128 occupants aboard the aircraft and eight persons on the ground. CAB determined that the probable cause was that the United Airlines flight proceeded beyond its clearance limit and confines of the airspace assigned by ATC. The DC-8's high speed, coupled with a change of clearance which reduced the distance which the aircraft needed to travel by approximately 11 miles, contributed to the crash. The Board concluded that the crew did not take note of the change of time and distance associated with the new clearance. The crew's workload was increased by the fact that one of their two VOR receivers was inoperative, a fact unbeknown to ATC.

FAA actions taken as a result of the accident included:

1. A requirement that pilots operating under instrument flight rules report malfunctions of navigation or communications equipment, effective 17 Feb 1961.

2. A programme to equip all turbine-powered aircraft with DME.

3. A speed rule, effective 18 Dec 1961, prohibiting aircraft from exceeding 250 knots when within 30 nautical miles of a destination airport and below 10000 feet, except for certain military jets requiring a higher minimum speed for safe operation.

4. Other steps to strengthen air traffic control procedures.

llanfairpg 13th January 2008 19:31

Speed was contributory but the main cause was

United Flight 826 proceeded beyond its clearance limit and the confines of the airspace allocated to the flight by Air Traffic Control.

S-Works 13th January 2008 19:34

With all due credit to you llanfairpg you know how to try and brow beat people into agreeing with you. Do you display the same dogmatic approach when driving the AP on the people tube?


:LOL:

llanfairpg 13th January 2008 19:51


Do you display the same dogmatic approach when driving the AP on the people tube?
Only above 250kts (with my scanner on)

frontlefthamster 13th January 2008 19:56

BEagle,

I'm not sure that that was the trigger for the limit in non-FAA States (it came to mind earlier, but I've a feeling that we already had the rule here...)

IO540 13th January 2008 20:28

Contacttower
Let me give you a decent reply then.

"Assuming one is flying around the packed airspace of Southern England "

It is busy only in some places, and mainly below 1500ft or so. In past 10 years, 11 UK mid-airs of which 10 below 1000ft and 1 reportedly at 1800ft.

Few in GA would fly at those levels if going somewhere "fast". Most serious VFR pilots fly as high as they can, clouds and airspace permitting. In the absence of weather/airspace one would fly at 4000+ft as this gives you calm air even on hot summer days. The best MPG (typical IFR tourer, non-turbo engine) is at 7000-10000ft.

"trying to get words in edge ways"

This is the way the PPL is taught (high radio workload, inside leg measurement supplied to every ATC unit within 2,000nm radius) but one doesn't actually do this when flying for real. You can go non-radio in Class G - no point in calling up any ATC enroute unless they can offer you a radar service, and if you get that, and give them your routing (A-B-C-D using navaid waypoints, not village names) they tend to leave you alone, with implicit MATZ transits etc. They are busy enough dealing with pilots who don't know where they are going or are non-transponding so nobody knows how high they are.

" while trying to stay aware of your position with nothing but DR and the map."

Why navigate WW1-style when there is no need to? Get a big moving map GPS, and your nav workload falls by at least 90%.

"At what speed does this simply become too difficult? At 100kts it's possible, but at 250kts say would it still be practical or would it just be a matter of time before you ended up busting airspace?"

I can't speak for dead reckoning (I don't do it) but the RAF seem to get about OK at higher speeds, allegedly with just maps, headings and timing. Mind you, they are the cream of the cream of the young men (those that don't make the grade used to become navigators and end up in the CAA :) ) and don't compare with civilian pilot recruits at all. They also have good ground backup and - due to generally poor fuel endurance - fly carefully preplanned missions. Some of them do have GPS; in fact any military plane that goes anywhere near any real action needs to have proper nav.

250kt at 3000ft would be a piece of cake, with a GPS - just follow the magenta line, manually or on autopilot. I've seen 220kt ground speed and it wasn't really noticeable; the ground below moves just a little faster than usual. I often wish I had 250kt IAS, to cover distances. Obviously one doesn't fly the circuit at 250kt.

Poor visibility is something else. You can fly legal UK-PPL VFR with 3000m vis, which is more or less total haze ahead. I don't see anybody dead reckoning in that, other than at a very low speed and low level. Very hard work.

Regarding the 250kt limit, this is 250kt IAS. With the TAS multiplier (in a 250kt IAS descent through/from FL100) and some tailwind, your GS could easily be 300-350kt and you would still be legal.

llanfairpg 13th January 2008 20:39


Mind you, they are the cream of the cream of the young men (those that don't make the grade used to become navigators and end up in the CAA
Or VC10 pilots


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