Ask The Pilot

[jb747]

I am internested in your opinion as to the safety of Air China (flights from either PEK or PVG to Melbourne/Sydney).
I have heard rumours that allege they may not be as safe as other major airlines.

Do you have an opinion?

I expect that many of the 'majors' that you mention are on my personal don't like list. If you don't like QF use Cathay.

 

[docjames]

In reality the vast majority of people don't care. The cheapest flight will suffice, and they figure the odds will cover the rest of it.

Guess I'm not in the vast majority.

 

[jb747]

So in that regard.. How is heading, altitude and speed selected seperately from the FMC, say, following a heading or altitude given by ATC?

All of the modes are autopilot/flight director modes. Managed means the commands are coming from the FMC, whilst in the other modes we control them by selections on the mode control panel. So, if given a heading by ATC, simply dial the heading selection to the number required, and then pull it to change to heading mode. Altitudes are also selected on the MCP, but don't necessarily entail a change of mode. If we are already climbing in a managed climb, then any entered altitude is simply a constraint on the climb. Open climb happens automatically with any selection of heading. V/S is generally considered a dangerous mode in the climb, but it is used in the descent.

What are your thoughts on the inability to be in a managed vertical mode? A simple inconvenience? Is there a reason behind it?

I'm pretty sure that their reasoning is that the vertical path was built assuming you'd be exactly on the programmed track and once off that track, the accuracy and rationale behind any given vertical path are suspect. It makes little practical difference.

 

[por930]

JB, I just did a return trip, Brisbane-Dubai-Paris in the A380. A few questions.


On the flight to Dubai about 12:20 at night when getting low and close to Dubai, we were doing several turns before eventual line up(apparently, the airport was busy). On one of the turns, the a/c appeared to 'hold up' into wind? engines and wind noise stopped, when the aircraft shuddered and slid sideways down in the direction of the bottom wing. About 3 seconds later, engines roared into life, dropped the nose a little, arrested the sideways slide down and we shot forward, a few more turns and then lined up for a very firm landing.


On the approach and landing at Brisbane, the Westerly winds were gusting quite fierce. Looking at the viewing screen, the a/c carried out the 01 approach pointed at the terminal and during the flare, pilot did not seem to change the direction much. We firmly landed pointing about some way off the centre line. The a/c momentarily skidded, wanted to follow its wheel direction, then the pilot straightened her up in a very fluid motion. If I am late getting out of the crab position in my Cessna, my tyres want to jump off their rims. Are the A380's better equipped for crosswind landings?


After several flights now in the A380, the landings seem much firmer that the 747-400...maybe just perception.

 

[Major]

Qantas has recently stated that it does not support the installation of an ILS at OOL because it is outdated and too costly.

What are the alternatives ?

 

[jb747]

On the flight to Dubai about 12:20 at night when getting low and close to Dubai, we were doing several turns before eventual line up(apparently, the airport was busy). On one of the turns, the a/c appeared to 'hold up' into wind? engines and wind noise stopped, when the aircraft shuddered and slid sideways down in the direction of the bottom wing. About 3 seconds later, engines roared into life, dropped the nose a little, arrested the sideways slide down and we shot forward, a few more turns and then lined up for a very firm landing.

It's very hard to assess anything that an aircraft is doing from the back. The A380 flight control system won't allow any substantial amount of sideslip, so I can be quite sure that it did not go sideways. Most likely you were simply doing a descending turn within either the holding pattern or the approach. The arrival to Dubai can be quite convoluted, and involves many turns, level and speed changes.

On the approach and landing at Brisbane, the Westerly winds were gusting quite fierce. Looking at the viewing screen, the a/c carried out the 01 approach pointed at the terminal and during the flare, pilot did not seem to change the direction much. We firmly landed pointing about some way off the centre line. The a/c momentarily skidded, wanted to follow its wheel direction, then the pilot straightened her up in a very fluid motion. If I am late getting out of the crab position in my Cessna, my tyres want to jump off their rims. Are the A380's better equipped for crosswind landings?

You can land will all of the drift intact on Boeings (which will get up up to around 16º). When I first read your comment, I'd assumed you were in a 777, as that's quite a normal landing technique, and is the Boeing recommended on a wet runway. But then I realised you were talking A380... Airbus have a 5º limit on drift at touchdown, and firm with drift is a definite no no. So, to be honest, it doesn't sound like much of a landing. The tyres are much more solidly attached, so pulling them off the rims isn't a normal consideration.

After several flights now in the A380, the landings seem much firmer that the 747-400...maybe just perception.

Not if you land it properly. Not much different.

 

[jb747]

Qantas has recently stated that it does not support the installation of an ILS at OOL because it is outdated and too costly.

What are the alternatives ?

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

How it works | Airservices


GLS is the obvious alternative. There's an installation in Sydney, which I have used to auto land on one occasion. I don't see that it will take away the requirement for a long finals, but it should be a much cheaper and easier option than an ILS.

 

[flychrisfly]

Escape tracks for high terrain are considerations in the event of a depressurisation. They are chosen to allow you to get out of the high terrain, within the duration of the passenger oxygen system. Aircraft that use oxygen generator systems only have from about 10 to 20 minutes of oxygen available, whereas bottle gas systems can have hours available.

Are there any regions of the world where the escape tracks result in a forced landing not on a runway?

 

[jb747]

Are there any regions of the world where the escape tracks result in a forced landing not on a runway?

Wouldn't be much of an escape track would it?

There are regions that airliners (or some particular types) don't overfly, for this, amongst other reasons (Himalayas). Big hills often equal nasty turbulence, so not good places to be anyway.

 

[flychrisfly]

Wouldn't be much of an escape track would it?

There are regions that airliners (or some particular types) don't overfly, for this, amongst other reasons (Himalayas). Big hills often equal nasty turbulence, so not good places to be anyway.

It would be a frying pan/fire type of scenario - one disaster at a time.

Do flight path constraints impact escape tracks? For example, I believe much of China's airspace is allocated to military and not civil aviation. Does this factor into escape track planning at all?

 

[andmiz]

Do flight path constraints impact escape tracks? For example, I believe much of China's airspace is allocated to military and not civil aviation. Does this factor into escape track planning at all?

The major consideration is terrain on our en-route diversion guides. In the event of a rapid decompression, an emergency would have been declared and we'd expect ATC cooperation; including military traffic...airspace in China however is a major headache. Most of our escape routes are on existing airways and hopefully away from military traffic, however we have a few company derived routes (off the airways) when the route/terrain is critical.
For instance, 'Y1' is a common route for our European traffic and it cuts across the northeast corner of the Himalayas. We have a company escape route when heading to Europe which leads off Y1 north east for a landing at Lanzhou (or onwards to Xi'an or Beijing); otherwise the safe altitude along that section of route is 20,000ft which would lead to issues following a decompression.

 

[Peasant]

Hi JB747, quick question on start-up for the 380.

Usually I hear four deep rumbles, which I assume is each of the four engines starting up (very obvious when the rest of the cabin is so quiet). Yesterday, I heard the rumble on our RR aircraft maybe 7 or so times, so I was wondering whether one of the engines was being a bit stubborn or whether something else might explain it? I understand the 380 uses auto start, which I assume has some similarities with the way our modern cars start, so I was just curious as it's the first time i've noticed it after many flights on the type.

 

[jb747]

Hi JB747, quick question on start-up for the 380.

Usually I hear four deep rumbles, which I assume is each of the four engines starting up (very obvious when the rest of the cabin is so quiet). Yesterday, I heard the rumble on our RR aircraft maybe 7 or so times, so I was wondering whether one of the engines was being a bit stubborn or whether something else might explain it? I understand the 380 uses auto start, which I assume has some similarities with the way our modern cars start, so I was just curious as it's the first time i've noticed it after many flights on the type.

It's hard to hear the engines starting from the coughpit. They are generally started in pairs; 1&2, then 3&4, though nothing forces that to be the order.

If the autostart aborts the start, the engine is allowed to run down, it will then automatically motor for cooling, and then run the start sequence again. The only difference on the second start being that it will use both ignitor system instead of one. If it fails to start the second time, then it's back to the engineers. In 3,000 hours on the aircraft, I can only recall seeing the start abort once...it's very reliable.

I suspect that the rumbling was a healthy start that was just taking its time to accelerate. A bit like many of us in the morning.

 

[Quickstatus]

Hi JB747,
IF QF8 had to refuel in NOU, would the crew still have enough hours to operate to SYD?.

 

[PointyEnd]

Gidday all! Noticed while round the back of a 380 the rudder is split. Is this a redundancy feature or do both parts work in tandem or together but in varying ratios?
Thanks in advance...

 

[jb747]

Hi JB747,
IF QF8 had to refuel in NOU, would the crew still have enough hours to operate to SYD?.

Noumea isn't a great choice for a planned refuel. Very restricted parking space and tight runway turning nodes. In an unplanned stop for fuel, the better option is Brisbane. If the stop has been planned, then Auckland becomes possible.

Time would be very tight, and anything more than about 40-60 minutes on the ground would probably run the crew out of duty time limits. For that reason, any time a diversion looks likely, the company will try to position a crew in either Auckland or Brisbane to take over the aircraft. Sometimes that also happens for the LA flights.

 

[jb747]

Gidday all! Noticed while round the back of a 380 the rudder is split. Is this a redundancy feature or do both parts work in tandem or together but in varying ratios?

The rudder is also split on the 747. Travel on the entire rudder system is limited as the aircraft accelerates (starting at 165 knots in the A380) to limit the overall loading on the fin. The upper section is limited to a greater degree than the lower. Even with restricted travel, there is always enough rudder available to counter the yaw induced by engine failure(s). The different sections of the rudder are powered by both of the hydraulic systems, as well as by three electrical systems. The 747 uses multiple hydraulic systems. There's plenty of redundancy.

 

[Quickstatus]

Noumea isn't a great choice for a planned refuel. Very restricted parking space and tight runway turning nodes. In an unplanned stop for fuel, the better option is Brisbane. If the stop has been planned, then Auckland becomes possible.

Time would be very tight, and anything more than about 40-60 minutes on the ground would probably run the crew out of duty time limits. For that reason, any time a diversion looks likely, the company will try to position a crew in either Auckland or Brisbane to take over the aircraft. Sometimes that also happens for the LA flights.

recently this happened with QF8 arriving in SYD at 0845 (arrived Friday 24/7/15) instead of 0630. Maybe the company positioned a crew there?

would crew replacement in these situations be tech and cabin crew?

 

[jb747]

recently this happened with QF8 arriving in SYD at 0845 (arrived Friday 24/7/15) instead of 0630. Maybe the company positioned a crew there?

would crew replacement in these situations be tech and cabin crew?

I gathered that it must have happened. I don't know the specifics of the event, so I can't comment on exactly what happened.

As I've said before, Noumea isn't at the top of the list for planned diversions. But, you rarely have the luxury of being able to plan them hours out. Mostly they are forced on you, fairly late in the piece. In the case of Australia, a recent change to the holding requirement rules has made long haul operations much harder, with exemptions for the requirements for ATC holding that used to be applied having been withdrawn.

For a crew to be in place, then the diversion, or at least the strong suspicion of one, would have to have been known about the previous night. Getting a crew to somewhere close (like Brisbane) would take about 5-6 hours from the decision to call them. Noumea...much harder. And that assumes that there's is a flight available to that destination.They aren't on airport standby, as that starts their 'clock', and so makes them useless for most operations.

Cabin crew hours are restricted by contract, and can be extended by the crew if they wish. Flight crew hours are restricted by law. Upshot is that it isn't uncommon for only the pilots to be replaced. Given that they were approximately 2 hours late, then they were most likely close to, but not outside, that limit. Even then, you can exceed it, as long as there was a reasonable expectation of not doing so when you departed (i.e. a flight time of 2 hours, when you have 2 hours available is okay...if ATC add some delay then you can't plan for that).

If you know that a diversion is likely, and have a few hours to spare, you can push the speed up as much as you can. Fuel consumption is probably irrelevant, as you're actually landing well short of your original destination. You won't save much time, but it all helps. Tricks like a late descent, with lots of speed brake along the way can save a few more minutes. Comfort becomes secondary to saving every second.

 

[Captain Halliday]

I gathered that it must have happened. I don't know the specifics of the event, so I can't comment on exactly what happened.

As I've said before, Noumea isn't at the top of the list for planned diversions. But, you rarely have the luxury of being able to plan them hours out. Mostly they are forced on you, fairly late in the piece. In the case of Australia, a recent change to the holding requirement rules has made long haul operations much harder, with exemptions for the requirements for ATC holding that used to be applied having been withdrawn.

For a crew to be in place, then the diversion, or at least the strong suspicion of one, would have to have been known about the previous night. Getting a crew to somewhere close (like Brisbane) would take about 5-6 hours from the decision to call them. Noumea...much harder. And that assumes that there's is a flight available to that destination.They aren't on airport standby, as that starts their 'clock', and so makes them useless for most operations.

Cabin crew hours are restricted by contract, and can be extended by the crew if they wish. Flight crew hours are restricted by law. Upshot is that it isn't uncommon for only the pilots to be replaced. Given that they were approximately 2 hours late, then they were most likely close to, but not outside, that limit. Even then, you can exceed it, as long as there was a reasonable expectation of not doing so when you departed (i.e. a flight time of 2 hours, when you have 2 hours available is okay...if ATC add some delay then you can't plan for that).

If you know that a diversion is likely, and have a few hours to spare, you can push the speed up as much as you can. Fuel consumption is probably irrelevant, as you're actually landing well short of your original destination. You won't save much time, but it all helps. Tricks like a late descent, with lots of speed brake along the way can save a few more minutes. Comfort becomes secondary to saving every second.

You've previously explained that flights where you are PAX for positioning reasons count as duty hours. In a case like a diversion to BNE where a new crew operates the sector to MEL after refuelling, can you PAX it (assuming an available seat) in order to get home to your family/own bed etc. or do the rules still apply and you're off to a Brisbane hotel for the night?