Ask The Pilot

[jb747]

Thanks, what is the setting a percentage of? As in, what does it mean?

Thanks again!

Centre of gravity, as a percentage of mean aerodynamic chord.

https://en.wikipedia.org/wiki/Center_of_gravity_of_an_aircraft

 

[Quickstatus]

So on the ND,

The air vector (a) (the direction the aircraft is pointing) is in the direction of 227deg
The ground vector (g) (the direction the aircraft is travelling) is 206deg
The wind vector (w) is 286deg

TAS is the air vector?





Can you please comment:
Using sine rule and 3 angles and W=186 kts
TAS along heading 206 = 444 kts
TAS along heading 227 = 511 kts (close approximation to TAS as displayed 480 kts)

(sorry how do you rotate image)

 

[jb747]

I think you're asking why the numbers don't seem to work. The secret is that whilst the heading and track are being displayed in magnetic, the wind is the true direction. So, the magnetic wind would be about 275º.

Try the numbers here: E6B Emulator

Use the Course, Ground Speed, And Wind Correction Angle calculator.

 

[Quickstatus]

From the D&C threads
QF1 diverted to LCA after departing DXB for LHR

Is Bucharest's OTP (...named after the discoverer of the Coanda effect - which keeps aircraft in the air...) A380 capable?



........

2)
http://www.australianfrequentflyer....lays-cancellations-52193-564.html#post1662605

In the end how close were you to predicted arrival fuel.

 

[Ansett]

JB how would this even be possible? and does it occur often?

Listen: Air Canada plane narrowly avoids biggest aviation disaster in history - NZ Herald

 

[clazman]

What are the red squares at the top of the airspeed?

 

[jb747]

From the D&C threads
QF1 diverted to LCA after departing DXB for LHR

Is Bucharest's OTP (...named after the discoverer of the Coanda effect - which keeps aircraft in the air...) A380 capable?

Nobody takes one there, so I'd have to assume not. There is a lot that makes an airport suitable or otherwise, not just the length of the runway. Taxiway widths, strength, and shoulders. Parking and refuelling. Obstacles.

We've discussed this before I think, but there is a world of difference between an airport that I might choose if bad things were happening to the aircraft and I just wanted to get on the ground, or those for normal diversions. In the first instance I may not care if I close their airport by blocking the runway. And this scales all the way back to the sort of airport and services that I need for a relatively normal diversion. A medical diversion is not an aircraft emergency (though it may be declared as means of getting priority), and as such you won't just choose any airport that happens to be around. The online medical services also have a big say in just where you go, as they have access to information about the medical facilities available...I have seen them choose a more distant alternate when two were available for that reason.

Turkish airports were available, but no longer. So that means Larnaca, then a gap to Vienna and Prague. A landing outside of Eurocontrol's area may also be a consideration, because, once you do land inside, you'll be subject to their slot control. A slot that's outside of possible crew duty limits is more likely than not.

2)
http://www.australianfrequentflyer....lays-cancellations-52193-564.html#post1662605

In the end how close were you to predicted arrival fuel.

The flight plan, or my prediction? About 2 tonnes under...

 

[jb747]

JB how would this even be possible? and does it occur often?

Listen: Air Canada plane narrowly avoids biggest aviation disaster in history - NZ Herald

Often...I hope not. But, takeoffs and landings on taxiways, or on wrong runways have a long history. It can be quite difficult to pick out runways at some locations, and airports that use non standard lighting or PAPI installations can add to the confusion. I expect that SFO were clearing the aircraft for visual approaches, so the ILS may not have been displayed. Procedurally, Airbus want the flight director turned off once you're into a visual approach (which ensures the auto thrust is in speed mode), so that can remove any guidance the aircraft may have been trying to give. I was at LAX the day the 737 landed on top of another aircraft, and have noted ever since how easy it is for aircraft to disappear into a sea of lights during night operations (though I don't know what time of day this happened).

 

[jb747]

What are the red squares at the top of the airspeed?

The bricks....They show maximum airspeed.

The limit is currently shown as about 273 knots. At low levels, the IAS limit is 340, but it dynamically becomes a mach limit as we climb. The mach limit is .89, but that does not equate to a fixed IAS...the bricks move to show the current limit.

At low levels, with slats/flaps extended, the bricks show the appropriate limit for the current configuration. During clean up after take off, you get very close to them at around the 210 knot area. The aircraft actually has an automatic retraction feature that is used in all heavy take offs, that automatically partially retracts to allow a higher speed limit (and reduce the loads). Basically, whilst we can select FLAP 1, the resulting configuration with be 1 or 1+F, depending upon the speed. Auto retraction starts at 212 knots, and takes the limit from 222 to 263 knots.

 

[Himeno]

I was at LAX the day the 737 landed on top of another aircraft, and have noted ever since how easy it is for aircraft to disappear into a sea of lights during night operations (though I don't know what time of day this happened).

The AC flight in question is due into SFO shortly after QF74 departs.

 

[Quickstatus]

I'm sure this has been asked before but what is the difference between altitude and flight level.
If there is a difference when does the aircraft systems / procedures transition between the two?.

 

[AviatorInsight]

I'm sure this has been asked before but what is the difference between altitude and flight level.
If there is a difference when does the aircraft systems / procedures transition between the two?.

Basically an altitude is flown below the transition level. In Australia this is 10,000ft on the way up and 11,000ft on the way down. Anything above this level/layer and it's referred to a flight level as everyone is on the same QNH setting.

In the US, it's 18,000ft, and somewhere in Europe (not sure where) it's as low as 3,000ft?

 

[jb747]

I'm sure this has been asked before but what is the difference between altitude and flight level.
If there is a difference when does the aircraft systems / procedures transition between the two?.

To expand upon that....at lower levels we care a lot about just how close the ground is. So, the altimeter pressure setting is adjusted to local QNH, which means that when that pressure is set on the altimeter, it will read the elevation above sea level. When on the ground, it will read the airport's elevation (more or less).

But, as you fly along, that local pressure is constantly changing, and it would be impossible to keep up with the changes. So, to ensure that all altimiters would read the same thing (at the same actual height), a standard setting is used. When using this, the reading on the altimeter is called a flight level. It may not be the actual altitude (the length of the bit of string to the ground), but as it's being used by all aircraft, it doesn't matter.

 

[RooFlyer]

Here is a bit of a reconstruction of the recent SFO incident involving Air Canada, along with the relevant ATC audio.

One thing that struck me was the unidentified voice that comes on at about 15 seconds (after AC wrongly 'confirms' the clear runway), that says "Where's this guy going ... he's on the taxi way".

It is mainly the tone of the voice that surprises me ... almost laconic, like a disinterested on-looker.

Question to pilots is, besides a possible 'hacker', who has access to the frequency that ATC and Air Canada would have been using, besides other aircraft pilots? Any theories what sort of user the mystery voice would be? [Edit: According to OMAAT (but unattributed), it was a United pilot, on the taxi-way]

If it was one of the crew of the planes on the taxi-way, I would have been inclined to say "Air Canada, go around! You are landing on occupied taxi-way" and be damned with protocols.

 

[andmiz]

If it was one of the crew of the planes on the taxi-way, I would have been inclined to say "Air Canada, go around! You are landing on occupied taxi-way" and be damned with protocols.

Not too sure, but the communication got the message across and time spent identifying theirselves, or trying to identify the Air Canada aircraft may have wasted critical seconds.
All it could have taken was another aircraft transmitting on the frequency regarding something completely different and removed the opportunity for the 'United pilot' to speak up.

 

[RooFlyer]

Sure No argument on that score; but you'd think the UA guy (if it was him) might have put a bit more emphasis into it If he got garbled out half way through, there was no indication that he was saying anything terribly important.

 

[flychrisfly]

Sure No argument on that score; but you'd think the UA guy (if it was him) might have put a bit more emphasis into it If he got garbled out half way through, there was no indication that he was saying anything terribly important.

Redirecting this speculation to the purpose of this thread: what would any of the pilots on this forum have done if they were on a taxiway and it appeared a plane would soon be landing on them?

 

[jb747]

Redirecting this speculation to the purpose of this thread: what would any of the pilots on this forum have done if they were on a taxiway and it appeared a plane would soon be landing on them?

Turn on all of the lights. Yell. With some airlines that would have no effect at all.

Practically, by the time you realise it's an issue, your ability to move a large aircraft out of the way (and it would have to be on to the grass) would be extremely limited, plus turning would make you an even bigger target.

 

[Quickstatus]

CG Question
CG implies balance in the fore-aft

As an aircraft travels in an air mass, would not such a balanced aircraft tend to change pitch, oscillate or at least be unstable in pitch?

 

[JessicaTam]

I recently flew in an an A330 MEL-SYD. Just before take-off the captain came over the PA to advise that the FO would be 'taking us to SYD'.

Are there any parts of a flight that the captain must carry out, or could she leave the whole thing to the FO and just observe?