Ask The Pilot

[juddles]

... why have any pilots at all.......

Why don´t ¨they¨start with driver-less buses and taxis. And semi-trailers on the national highways. Should be easy....

 

[jb747]

If the designated alternative to a destination has long hold times, does the pilot have to divert to another alternate in case of problems with destination?

Ah, an alternate to an alternate.

Basically, if an airport has forecast weather that is below the 'alternate criteria' for a specified period, then you need to have fuel to hold for the period of the weather (i.e. TEMPO or INTER, 60 or 30 minutes), OR an alternate. If there is no specified period (i.e. the weather is there all day), then you outright need an alternate.

Your alternate cannot itself require an alternate...otherwise you'll have to have its weather holding too.

ATC holding is a little different. Generally you only need one lot of it.

Eg LAX-MEL , alternate SYD long hold times due to say fog/weather.

On the sector you use as an example, you would be very unlikely (to have sufficient fuel) to be able to actually go to Melbourne, and then divert back to Sydney...so it isn't really an alternate. In that case you'll make an assessment of what is happening at Melbourne, and either fly past Sydney to a diversion point (roughly Canberra), and then return to Sydney, or just give in to the inevitable, and go to Sydney early.

 

[mjt57]

There is no doubt that levels of automation will increase. But, they have already hit the point at which automation is causing a degradation in pilot skills (and in other cases preventing them from developing in the first place).

This is the same with a lot of industries, including where I work.

I thought that the idea of having two pilots, other than to share the workload is that if one becomes incapacitated the other can continue to fly the aircraft.

As a semi-regular infrequent flyer the idea of having a single pilot up front is not something that endears me to a relaxing flight. Certainly, if the day ever comes that automation is such that they will hire some kid who's an expert on his Playstation to sit in a room somewhere then for me at least, it will mean that my future holidays may well be with a 'van on the back of the Prado...

 

[opusman]

There's apparently been a lot of fuss and bother from pilots in the US recently, relating to their use of cameras etc. in the coughpit.

Just wondering what regulations CASA and/or QF have regarding this in Australia?

 

[jb747]

There's apparently been a lot of fuss and bother from pilots in the US recently, relating to their use of cameras etc. in the coughpit.

Just wondering what regulations CASA and/or QF have regarding this in Australia?

I think there has been some troublemaking from one source...and most people are quite content to leave it at that.

 

[747sp]

Many thanks to the pilots and experts who answer the question and it has given me a much better understand of the difficulties facing the flight crews.
I was on QF 7 ( great flight ) and when the captain gave the details of the flight just before take-off he advised that we should expect rough weather near Fiji and perhaps for last hour of the flight before we land . He was 100 % right and on both cases he was the one to advise us to do up the seat belts.
My question is on a longer flight where there is more than 2 crew would the captain normally try and arrange the shifts so they would be either flying or observing at key points of fight when bad weather is forecast or does that get too difficult especially if long periods of turbulence are forecast ?

 

[jb747]

Many thanks to the pilots and experts who answer the question and it has given me a much better understand of the difficulties facing the flight crews.
I was on QF 7 ( great flight ) and when the captain gave the details of the flight just before take-off he advised that we should expect rough weather near Fiji and perhaps for last hour of the flight before we land . He was 100 % right and on both cases he was the one to advise us to do up the seat belts.
My question is on a longer flight where there is more than 2 crew would the captain normally try and arrange the shifts so they would be either flying or observing at key points of fight when bad weather is forecast or does that get too difficult especially if long periods of turbulence are forecast ?

Over some parts of the world, where there are very high safety heights, it might be a company requirement for the Captain to be on duty, but unless it's something quite exceptional, then the FOs are more than capable of dealing with any weather that you may come across.

Of course, if it's going to be really rough, and ruin your time off, then some might be cheeky enough to ensure that they're on then.....

 

[mjt57]

JB, when you are setting up for a trip, how do you work out how much fuel you need to add? Do your indications show existing fuel levels/quantities in weight, volume or percentage of what's in each tank? And does it calculate what you need or do you have to get out graphs or calculate it all with the iPad or whatever?

And when they refuel it do the pumps measure it in volume or weight/mass?

I can't imagine the fuelling systems having the "auto click" shutoff system. Or do they?

 

[jb747]

JB, when you are setting up for a trip, how do you work out how much fuel you need to add? Do your indications show existing fuel levels/quantities in weight, volume or percentage of what's in each tank? And does it calculate what you need or do you have to get out graphs or calculate it all with the iPad or whatever?

The company will provide a flight plan which shows the minimum legal fuel for a sector. I can leave it at that, add some, or, in some very rare cases, even remove a bit. I'm only really interested in the total figure. I don't care what fuel is already on the aircraft, or which tanks it's in...that will be taken care of during the refuel.

And when they refuel it do the pumps measure it in volume or weight/mass?

When they refuel, they enter the target fuel quantity onto the refuelling panel (of the aircraft). The fuel management system will ensure it goes to the correct tanks, and is appropriately balanced. Unusual loads do happen sometimes...some we'll just accept, whilst others we'll correct by using the fuel system to move it to a standard distribution.

The system uses volume and specific gravity to calculate the fuel mass. We only deal in mass (kgs).

I can't imagine the fuelling systems having the "auto click" shutoff system. Or do they?

It's rather smarter than that, but in essence....

 

[mjt57]

When they refuel, they enter the target fuel quantity onto the refuelling panel (of the aircraft). The fuel management system will ensure it goes to the correct tanks, and is appropriately balanced. Unusual loads do happen sometimes...some we'll just accept, whilst others we'll correct by using the fuel system to move it to a standard distribution.

Is the refueling panel in the coughpit or do the refuellers access it outside somewhere?

And can I assume that there are smarts which talk between the A/C fuel system and the refuelling system?


[/QUOTE]

 

[Boris spatsky]

Is the refueling panel in the coughpit or do the refuellers access it outside somewhere?

And can I assume that there are smarts which talk between the A/C fuel system and the refuelling system?

It depends on the aircraft type. Some are in the wing, some are on the overhead panel in the flightdeck. Yes, the panel if external talks to the aircraft fuel system.

 

[knasty]

I have noticed that often thrust is reduced when entering an area of turbulence. Is this for the comfort of the passengers, to reduce the likelihood of excessive speed, or some other reason please? Thanks.

 

[jb747]

It depends on the aircraft type. Some are in the wing, some are on the overhead panel in the flightdeck. Yes, the panel if external talks to the aircraft fuel system.

They are normally on the outside of the aircraft, where they are readily accessible to the engineers. If anything, they're a bit like the refuelling bowsers where you set your price limit. You set the amount you want, and then it should shut off at the appropriate time.

The panel in the coughpit is for in flight use, and it allows us to control where the fuel is coming from, and, if necessary, to force transfers out of the normal sequence.

 

[jb747]

I have noticed that often thrust is reduced when entering an area of turbulence. Is this for the comfort of the passengers, to reduce the likelihood of excessive speed, or some other reason please? Thanks.

Thrust is only adjusted to control the speed. We don't as a matter of course, reduce speed in areas of turbulence. The turbulence speed, is basically the normal cruise speed anyway. The available speed margin is often very narrow, both in terms of going faster or slower. If the aircraft gets a bit too fast, it's easily corrected with power, or speed brake if necessary. But, if it gets too slow, only a few knots below min drag (Airbus green dot), you will not have sufficient power to accelerate again, and the deceleration will continue. The only solution then is to descend...which is bad.

So, within areas of turbulence, you may notice power changes, but they will generally be in both directions, and the aircraft often hit max power in these areas.

 

[RooFlyer]

In another thread it appears that a domestic flight pushed back and started taxiing and the ground crew at least may have known that a pax had failed to board while having checked bags still on board when the aircraft pushed back. Aircraft subsequently returned to the gate where the pax boarded and the flight then departed normally.

Ignoring the details of that particular situation, I'm wondering if the 'paperwork' presented to the coughpit prior to doors closing includes any statement from the ground handlers/FAs to the effect that yes, there are no un-accompanied bags on the fight because they have accounted for all the checked-in pax and offloaded any bags of anyone who failed to board. The pilot in charge then accepts that statement and deems that safety item able to be ticked off.

Or is that not in the minutiae of the coughpit departure checklist and so a detail signed off by others?

 

[jb747]

In another thread it appears that a domestic flight pushed back and started taxiing and the ground crew at least may have known that a pax had failed to board while having checked bags still on board when the aircraft pushed back. Aircraft subsequently returned to the gate where the pax boarded and the flight then departed normally.

Ignoring the details of that particular situation, I'm wondering if the 'paperwork' presented to the coughpit prior to doors closing includes any statement from the ground handlers/FAs to the effect that yes, there are no un-accompanied bags on the fight because they have accounted for all the checked-in pax and offloaded any bags of anyone who failed to board. The pilot in charge then accepts that statement and deems that safety item able to be ticked off.

Or is that not in the minutiae of the coughpit departure checklist and so a detail signed off by others?

What is the reference to the other thread?

Basically we are closed up below by the ground handling people. Final passengers board. A 'ramp clearance' is issued by the ground staff, which goes to load control, and allows them to generate the final load sheet. I'll go as soon as all of the doors are shut, and I have that load sheet.

Discussion of offloading only happens when people have failed to board, when there will be specific queries about their luggage.....in the normal course of events, I'll see doors below close, ACARS will ping with the load sheet, and then as soon as doors above close, we'll ask ATC for a push clearance.

 

[Major]

http://www.australianfrequentflyer....houd-jetstar-have-done-65089.html#post1170186

 

[jb747]

This is why the fully automated aircraft is still quite a way in the future. There was no procedure to correct the issue, the pilots made it up on the spot. The system concerned is there to stop the aircraft from being stalled....

Following the occurrence EASA released ​

emergency airworthiness directive 2014-0266-E_1

stating:​

An occurrence was reported where an Airbus A321 aeroplane encountered a blockage of two Angle Of Attack (AOA) probes during climb, leading to activation of the Alpha Protection (Alpha Prot) while the Mach number increased. The flight crew managed to regain full control and the flight landed uneventfully.

When Alpha Prot is activated due to blocked AOA probes, the flight control laws order a continuous nose down pitch rate that, in a worst case scenario, cannot be stopped with backward sidestick inputs, even in the full backward position. If the Mach number increases during a nose down order, the AOA value of the Alpha Prot will continue to decrease. As a result, the flight control laws will continue to order a nose down pitch rate, even if the speed is above minimum selectable speed, known as VLS.

This condition, if not corrected, could result in loss of control of the aeroplane.

 

[Tortuga]

There seems to be a lot of issues caused by blocked probes - is there any new developments in the works that you are aware of to prevent them getting blocked?

 

[jb747]

There seems to be a lot of issues caused by blocked probes - is there any new developments in the works that you are aware of to prevent them getting blocked?

There are a number of related items that can be affected by this. On the FBW aircraft, there are multiple probes reading angle of attack and sideslip, as well as the normal pitot and static probes. Loss of any of them should be a relatively minor event if handled correctly. For instance you do not need airspeed information (or altitude really), to fly an aircraft. The correct power setting, associated with the right attitude should give you any desired performance outcome.

What seems to be an issue at the moment is that the FBW systems can have responses that aren't all that well thought out. For instance, there was a recent Lufthansa incident in which icing of the angle of attack probes caused the FBW to engage in 'Alpha Prot' mode, which is there to stop pilots from stalling the aircraft. Trouble was that it was nowhere near stalling, and the system response of nose down pitch, which CANNOT be overridden on the joystick, was exactly the wrong outcome. Thankfully there were some actual pilots on board, who not only quickly decided they wanted to get rid of this 'safety' system, but also came up with a way of doing so. Sadly, the motto of many of the people involved in inventing these systems seems to be "it will not happen". Rather like Bagdad Bob denying there were American tanks in Bagdad, even though one was clearly visible in the background.

There is no guaranteed technical response. Don't fly in icing conditions might work...but that would mean not flying.