Because THAT calculation is based on the minimum rate of climb required for terrain clearance criteria. Obviously most aircraft climb at greater than minimum rate of climb and once high enough, the speed is irrelevant. As an extreme example, if you were 7000' 3 miles from PORPA do you think it would matter then?

Cancel speed restriction is clearance to cancel ALL speed restrictions issued by ATC which includes any speeds on charts. It does not cancel speed restrictions imposed by your Company SOP's. (250kts to MSA)

Cancels ALL ATC speed restrictions. Balls to the wall, but, Company limits still apply of course. i.e. 250k until above MSA.

Agreed CP Dude, of course it matters not if you accelerate when above radar lower safe or MSA, of course you cant hit anything if you blow out the turn. Agree entirely, but my question was what calcs do ATC do to clear the requirement? What do the departure controllers implement to clear us when there is an obstacle defined restriction? Is it simply a matter of observing our current ROC?

Correct for Light Twins; however, don't forget that in a big grown up aeroplane you can goto Vref +100 below MSA which could be 280kts+ :ok:

Lowkoon,

Departures paths use criteria based on minimum values to determine terrain clearance. These are based on the minimum rate of climb required as is stated as "standard" with either PANOPS or TERPS etc. My memory fails me but I believe it's about 200'/nm on departure. Any departure which requires a higher ROC will have the minimum ROC required posted on the departure sheet.

Based on the minimum ROC the turn at PORPA allows for only a turn radius associated with a speed of 220kts. Not being an ATC type, I'm not sure what formulas are programmed into their computers but I'm sure they can automatically calculate your current altitude, ROC and speed and make the calculation seamlessly and automatically for the controller to then clear you unrestricted or high speed.

White None,

You are correct once cleared for high speed.

Who knows if they even need a formula....? When you're cleared for high speed before Porpa, you're normally ALREADY above the highest piece of rock on your departure track before they give it.

On the 'bus it's the greater of 250kts or green dot speed. On a heavy 340, GD can be up towards 280kts. Does that mean that the A340 is a big grown up aeroplane too? :)

STP

STP,

No. The evidence is hanging on the wings.

If you were really big and grown up, you wouldn't need to ask ATC to go faster than 250kts!

STP

Sorry, according to the rules doesn't qualify. It HAS to be 280+. Love to help but..... Cannot, (Not that I'm displaying the raging inferiority complex all Jumbo drivers will vehemently deny now that the BigBus is around). :{

While at the hold it's nice to look down into the cockpit of the Bigbus next to you. :E

You can look down on me from your freighter any time you like with that 'I'm flying rubber dog**** out of Hong Kong' smirk.

I Love Rubber Dog****. It doesn't get lost/pissed in the terminal, it doesn't pinch my bum. It doesn't bleat if we're late or require apologies for stuff out of my control. It doesn't say "Cannot". It doesn't expect me to buy it, and it's mate's dinner and it always respects me in the morning.

Sshhh.... ;)

So is flying the freighter that good? Maybe the pay and rosters are not as bad as some make out!

Treboryelk
 

You are Nick Rhodes and I claim my £5. ;-p

Trevor the Moose

Amazing that so many in the company STILL!! don't know that most of us fly both, on the same pay. Having the seniority to do so I now get to pick either and where poss, fly freight. Why?.... See above.

Good stuff....though sounds like you wont be in a hurry to fly the -8i if Cathay buys them?

Love the thread creep.

Ok,

Now that this thread has gone "Off Topic" with the usual "im better than you" BS.

I have another ATC question.

The requirements at FL130 inbound to HKG, if ATC clear you below can we disregard the restriction?

If not, often they descend us to an altitude, do we have to maintain STD until passing the waypoint, ie pass at FL130 ISO 13000 on QNH (on our charts the restriction is FL130)

I would be interested in hearing from the ATCer's on this one.

JY