Ask The Pilot

[flyer89]

Interesting feature. Apparently wasn’t on earlier A350s and is being retrofitted.

 

[jb747]

Interesting feature. Apparently wasn’t on earlier A350s and is being retrofitted.

Pity the cabin data isn't showing any need for a descent.

It's a reasonable feature to add to the aircraft. But, it's simply one more autopilot function...this will still need to be practiced with, and without autopilot. And probably in degraded laws as well.

In the olde days, when I flew the Classic 747, emergency descents were always flown manually. The autopilot was never used. The -400 turned up, and the system did a 180, with the new assumption being that it would be safer and more logical to do the descent with the autopilot engaged. That was the state of play from '89 until '08, when we actually had need of the procedure. And guess what didn't work.

I

 

[flyer89]

Pity the cabin data isn't showing any need for a descent.

It's a reasonable feature to add to the aircraft. But, it's simply one more autopilot function...this will still need to be practiced with, and without autopilot. And probably in degraded laws as well.

In the olde days, when I flew the Classic 747, emergency descents were always flown manually. The autopilot was never used. The -400 turned up, and the system did a 180, with the new assumption being that it would be safer and more logical to do the descent with the autopilot engaged. That was the state of play from '89 until '08, when we actually had need of the procedure. And guess what didn't work.

My friend who flies said airplane claims he has no intention of using it. So there you go...

 

[Quickstatus]

So what’s left for the pilots to manually do?

 

[odysseus]

So what’s left for the pilots to manually do?

Start her up

 

[Captain Halliday]

Start her up

And save the day when an O2 bottle or an engine goes bang!

But thankfully not every time.

 

[Quickstatus]

Aviators,

VH-OQF recently operated without passengers SYD-BNE // BNE-SYD (23 April 2019)

Apparently this was a "Compass Swing" at Brisbane

Did something happen that increased the errors in the compass
Why did it need to go to BNE for this and not SYD?.
Is this a routine service item for all aircraft?

 

[AviatorInsight]

Aviators,

VH-OQF recently operated without passengers SYD-BNE // BNE-SYD (23 April 2019)

Apparently this was a "Compass Swing" at Brisbane

Did something happen that increased the errors in the compass
Why did it need to go to BNE for this and not SYD?.
Is this a routine service item for all aircraft?

It is a routine service item. For air transport aircraft it basically depends on the maintenance program that CASA have approved.

As far as did something happen? Here is a list of what could warrant a compass swing:

• When a compass is initially installed or reinstalled in an aircraft.
• After an engine change, unless the manufacturer prescribes otherwise.
• Whenever a magnetic sensing element has been changed or relocated.
• After modification of an electrical or avionic installation in the aircraft, unless the certifying engineer is satisfied that the modification will not affect the compass.
• After a lightning strike, unless at least two heading checks 90o apart shows that no change of deviation has occurred.
  Note: A heading check may be made during the flight on which a strike has occurred if this procedure is documented in the appropriate aircraft manual. Refer to the section of this AWB dealing with lightning strikes and aircraft demagnetisation.

• After any maintenance involving the addition, removal, or relocation of magnetic materials likely to influence compass deviation.
Note: Maintenance manuals may indicate the components that, if changed, would require the compass to be swung.

• Following any operational occurrence, such as an accident, or heavy landing, that is likely to affect compass deviation.
• After long-term storage of the aircraft.
• Whenever there is reason to suspect that a change of deviation
  may have occurred.
• Whenever the aircraft is relocated to a significantly different latitude.

 

[Quickstatus]

Interesting thank you,

Why did it need to be done in BNE?

Could cargo interfere with the Compass? How can this be mitigated after the cargo is uploaded?

 

[jb747]

VH-OQF recently operated without passengers SYD-BNE // BNE-SYD (23 April 2019)

Apparently this was a "Compass Swing" at Brisbane

Did something happen that increased the errors in the compass
Why did it need to go to BNE for this and not SYD?.
Is this a routine service item for all aircraft?

Compass swing...now that is a term from the past. I haven't done one of those since my days in the RAN.

All you never wanted to know about them:

Aircraft Compass Swing

The steps to perform a compass swing are reviewed, as a new product designed to save time and headaches when performing the task is examined.

www.aviationpros.com

AWB 34-008 Issue 2 - Calibration of Compasses - Civil Aviation Safety ...https://www.casa.gov.au/file/78931/download?token=1eWpKJk5

I expect that it couldn't be done at Sydney as it takes a fair bit of time, out on open magnetically surveyed tarmac...if such a thing exists in Sydney.

It would be covered somewhere in the normal maintenance of the aircraft, but the only magnetic compass that airliners have these days is the tiny emergency one on the centre pillar of the windscreen. Heading is calculated from true heading data generated by the IRUs...so nothing to 'swing'.

I'd put this into the extremely unusual category.

 

[serfty]

Very little information here: QANTAS A380 VH-OQF Brisbane Compass Swing Visit. | The QANTAS Source

 

[Quickstatus]

As the “compass” in the A380 is “digital” (inertial reference unit consisting of a laser gyroscope) a compass swing recalibration must then be for the backup analog compass - probably the tiny emergency one that @jb747 refers to.

Glad to see the degree of maintenance that goes on.. and it was originally a surprise to me as I thought all modern commercials had done away with analog compasses

 

[Fergo747]

Pilots, looking at DFW via google satellite (as you can tell, busy at work), I noticed that the parallel runways to the left of the terminal are 36/18 L,R and the parallel runways to the right of the terminal are 35/17 L,C,R although all five of them appear parallel.

Is the reason that these seemingly parallel runways are numbered differently because you can only have L, C, R as they don't appear offset to warrant a change in heading?

 

[Aus ATC]

Is the reason that these seemingly parallel runways are numbered differently because you can only have L, C, R as they don't appear offset to warrant a change in heading?

Correct - the runway numbers are an approximation of the magnetic heading. Similar at other airports such as CDG (09/27L+R to the north, and 08/26L+R to the south) or LAX (06/24 L+R to the north, and 07/25L+R to the south) - and no doubt plenty of other airports around the world.
My home town, BNE has RWY 01R, 19L (awaiting the new runway which will be 01L/19R) but it is aligned 016/196 degrees magnetic, so strictly speaking should be 02/20.

 

[serfty]

re numbered differently because you can only have L, C, R as they don't appear offset to warrant a change in heading

@jb747 has mentioned this before. ISTR It being to avoid confusion.

 

[RSD]

A question for JB747 - on the A380 - besides allowing left/right and forward back movements and then turning these into control surface movements, does the side stick allow itself to be rotated left/right and if so what does that control?

 

[jb747]

A question for JB747 - on the A380 - besides allowing left/right and forward back movements and then turning these into control surface movements, does the side stick allow itself to be rotated left/right and if so what does that control?

No, it's fixed in yaw. The aircraft has normal rudder pedals.

 

[RSD]

No, it's fixed in yaw. The aircraft has normal rudder pedals.

Thanks JB747. Are there some aircraft that control the rudder via rotating the stick instead of the pedals?

 

[jb747]

Thanks JB747. Are there some aircraft that control the rudder via rotating the stick instead of the pedals?

No aircraft. Spacecraft perhaps....

It would be a control nightmare keeping your commands in the correct plane.

 

[RSD]

No aircraft. Spacecraft perhaps....

It would be a control nightmare keeping your commands in the correct plane.

We use something like this with underwater remotely operated vehicles where we are controlling six thrusters through a joystick, we are perhaps fortunate that these vehicles move at a slower speed than an A380, but twisting the stick gives us the same response as a rudder on an aircraft but with no forward movement.