Ask The Pilot

[juddles]

Pilots, a couple of days ago I was a pax on the QF28 flight SCL-SYD that did a diversion to AKL due to a medical emergency on board. As per most of the questions in this thread, the following is nothing more than to satisy my curiosity, and to learn even more about flight and travel etc:

It would seem obvious to me that to make such a diversion (especially after we already had a three hour delayed departure from SCL), the consequences to the airline are very big. Would set off a chain of events and costs including everything from hotels for hundreds of pax and the need to get the whole network/dance of airframes back to normality. I also understand that making a call to divert is a hard thing in a medical case (would be so much clearer with a major mechanical malfunction) as the state of need of the pax must be very hard to judge.

What my specific question is, after such an event does some sort of debriefing/analysis/checking occur with the crew and decision makers?

 

[Captain Halliday]

New roster out now....

Including the current roster:
09/07 QF35
10/07 QF36

14/07 QF93
15/07 QF94

22/07 QF93
23/07 QF94

06/08 QF93
07/08 QF94

16/08 QF93
17/08 QF94

23/08 QF93
24/08 QF94

05/09 QF35
06/09 QF36

10/09 QF35
11/09 QF36

15/09 QF35
16/09 QF36

The last couple of 35/36s might be in doubt, but TBA closer to the event.

Miss you by two days... unless those 35/36s change. I’m on QF35 on 08/09.

 

[opusman]

Why does it often feel during take-off that there are speed bumps on the runway?

 

[jb747]

The most likely change to those Singapore trips is that I’ll be dropping all three of them. I’ve got a minor operation planned, and whilst I’ve built in a gap long enough for the time the specialist says I’ll need, the two DAMEs (aviation docs) that I’ve spoken to have both said they won’t sign me back out for a month.

 

[jb747]

Why does it often feel during take-off that there are speed bumps on the runway?

The ones that are ‘thump-thump-thump’ in very rapid succession? They’re the runway centreline lights. It’s nice if you straddle them with the nose gear, but that’s more accurate than most people can drive their cars, so it doesn’t always work.

There are much larger humps on some runways, but whilst you can see them, you can’t feel them.

 

[straitman]

Why does it often feel during take-off that there are speed bumps on the runway?

Poorly built joins in the concrete or bitumen and lack of heavy duty suspension that you get in a car.

Also to expand on jb747’s answer. On pilots course it is hounded into you to stay on centreline all the time. - except if there is centreline lighting in which case you ‘should’ stay just off centreline.

 

[jb747]

I recently watched a YouTube of starting up an A320 from cold and it looked very involved. There were switches and lights all over the coughpit most requiring a test procedure before selection of flight position, all very time consuming.

The sequence that is followed is very specific, but basically you start in one corner, and follow a defined sequence. When I first moved to the 380 we were all a bit taken back by how slow it was, taking us about 30 minutes, but now I can start a cold 380 in 12-15. Some of the tests you have to wait for the finish, but many you can just initiate and move on, and they will set off an ECAM if they fail. The switches that you mention are really the simple part, and the desired outcome is for all of the overhead lights to be out. The time is consumed by the FMC.

IRU alignment is the longest operation, taking about 9 minutes, and you need them aligned before the some other items will come up. You learn to do a few things out of sequence, as it is faster.

Is it necessary to cover the same ground where the turn around time might be an hour or less? Is there a method of recording that the checks have been performed and the results obtained?

Whilst some items can be left out on a turnaround, with the same crew, that’s something that is so rare on the 380 that it’s easier for us to just do the complete checks.

Results are pass or fail. If a test passes, we no longer care about it. If it fails, it becomes a tech log item, and any outcome will be recorded there.

 

[jb747]

Poorly built joins in the concrete or bitumen and lack of heavy duty suspension that you get in a car.

Some of the taxiways at Melbourne really qualify as poorly built. There’s one spot towards the southern end of A, which we really crash over.

On pilots course it is hounded into you to stay on centreline all the time. - except if there is centreline lighting in which case you ‘should’ stay just off centreline.

And it’s amazing how that being ‘hounded’ really stays with you. Even slightly off the centreline feels horrible. It applies to anything that you have control over. Flying near the altitude isn’t good enough...it takes just as much effort to fly consistently off the altitude as it does to fly right on it. A comment that often came up in formation flying, but which applies to a lot of aviation...”grit your teeth and get in there”.

 

[jb747]

Pilots, a couple of days ago I was a pax on the QF28 flight SCL-SYD that did a diversion to AKL due to a medical emergency on board. As per most of the questions in this thread, the following is nothing more than to satisy my curiosity, and to learn even more about flight and travel etc:

It would seem obvious to me that to make such a diversion (especially after we already had a three hour delayed departure from SCL), the consequences to the airline are very big. Would set off a chain of events and costs including everything from hotels for hundreds of pax and the need to get the whole network/dance of airframes back to normality. I also understand that making a call to divert is a hard thing in a medical case (would be so much clearer with a major mechanical malfunction) as the state of need of the pax must be very hard to judge.

The particular flight you were on was delayed, but that delay was built into the crew's roster before departure, so that particular 3 hours didn't affect things (for them anyway). The cost of the diversion, and all of the other juggling that has to be done is an SEP, and as such not something the crew should even consider. Since the advent of the always available medical services such as Medlink, the decision to divert has become much simpler. They will tell you if they consider it necessary, and they will make the medical arrangements (ambulance/hospital, etc) for wherever you choose to go. They will also advise you of the medically preferred diversion, though whether that's acceptable from an aviation point of view is up to the Captain. IOC will make arrangements for everything that's not medical or aviation, but they have no real input into the decision.

What my specific question is, after such an event does some sort of debriefing/analysis/checking occur with the crew and decision makers?

Some groups are much more in love with debriefing than others. The pilots will generally say whatever they have to say in the coughpit, or if a more extensive debrief is required, in the bar. The people in IOC/Sydney may have looked back at how it went, but unless the Captain or CSM had something particularly negative to say, that would just be 'in house'.

The only debriefs I've ever attended involved QF30...so a long way up the scale of seriousness.

Somebody else's problem - Wikipedia

 

[Himeno]

On last nights QF12, the flight crew said they had 1.5 ton more fuel loaded to fly faster. How much faster would that have allowed them to go?

 

[Boca68]

The particular flight you were on was delayed, but that delay was built into the crew's roster before departure, so that particular 3 hours didn't affect things (for them anyway). The cost of the diversion, and all of the other juggling that has to be done is an SEP, and as such not something the crew should even consider. Since the advent of the always available medical services such as Medlink, the decision to divert has become much simpler. They will tell you if they consider it necessary, and they will make the medical arrangements (ambulance/hospital, etc) for wherever you choose to go. They will also advise you of the medically preferred diversion, though whether that's acceptable from an aviation point of view is up to the Captain. IOC will make arrangements for everything that's not medical or aviation, but they have no real input into the decision.



Some groups are much more in love with debriefing than others. The pilots will generally say whatever they have to say in the coughpit, or if a more extensive debrief is required, in the bar. The people in IOC/Sydney may have looked back at how it went, but unless the Captain or CSM had something particularly negative to say, that would just be 'in house'.

The only debriefs I've ever attended involved QF30...so a long way up the scale of seriousness.

Somebody else's problem - Wikipedia

Well that helps answer my follow up question. I was on another QF28 perhaps a week before @juddles , we also had a medical emergency approximately half way through. Remember been woken by the call for medically trained passengers. Basically we were in the middle of nowhere. About 6 hours into what turned out to be 14+hours.

In the end we arrived in SYD, to be held on the plane for about 30 minutes to allow for medical crews to assess.

My question now, @jb747 , is the Medlink service available to a crew in the very far reaches of the Antarctic Ocean on QF28? Is there a Sat-Link? or other comm device to enable a medical decision/diagnosis?

 

[lastrow]

IRU alignment is the longest operation, taking about 9 minutes, and you need them aligned before the some other items will come up. You learn to do a few things out of sequence, as it is faster.

I've just been reading about IRU alignment and to the uninitiated the process seems rather complicated with plenty of opportunities to introduce errors. An important point raised was the necessity to not necessarily accept the stored last position data as an error will be introduced if the aircraft is towed to another gate.
How important is the INS these days when GPS is so widely available and not subject to possible miss reads due to reliance on data from inertia readings.

 

[jb747]

I've just been reading about IRU alignment and to the uninitiated the process seems rather complicated with plenty of opportunities to introduce errors. An important point raised was the necessity to not necessarily accept the stored last position data as an error will be introduced if the aircraft is towed to another gate.
How important is the INS these days when GPS is so widely available and not subject to possible miss reads due to reliance on data from inertia readings.

The IRU's navigation data is actually a secondary function. Its main role is provision of attitude and heading data, which on the scale of things, is much more important than position information. The FMCs integrate all of the various forms of navigation information, from GPS through INS to radio aids, to come up with their version of the position. Pulling up the raw position data in an FMC will sometimes show differences between the GPS positions (as well as between the IRS). A single GPS is not accurate enough for use with the RNAV approaches now flown.

There's not much room for error really. In most GPS equipped aircraft, the IRS will automatically align to the GPS position during the alignment phase. You can insert a gate position, but I don't recall the last time I did that. A small error will simply make the alignment phase take longer. Moving the aircraft during alignment will cause it to fail. Air Asia managed to input a position that was many thousands of miles away, and whilst I don't recall exactly what their system did, the aircraft was never happy, and gave them innumerable warnings and clues, all of which they ignored, or actively suppressed.

The most basic test of all...modern aircraft all have an electronic map, as a main flight display. If it places you anywhere other than the airport you're at (exactly at the appropriate gate), then that's perhaps a glowing neon light pointing to the fact that something is wrong.

 

[AviatorInsight]

I've just been reading about IRU alignment and to the uninitiated the process seems rather complicated with plenty of opportunities to introduce errors. An important point raised was the necessity to not necessarily accept the stored last position data as an error will be introduced if the aircraft is towed to another gate.
How important is the INS these days when GPS is so widely available and not subject to possible miss reads due to reliance on data from inertia readings.

Interesting you mentioned this, because this happened in ADL this morning. We noticed it was actually taking longer than normal to align, even though I had entered the GPS position into the FMC. So we did a little troubleshooting and on the display itself (see pic 2) on the right hand side is a fault code (04) we looked it up and turns out the IRS coordinates and the GPS coordinates we had at the gate didn’t match as the aircraft was on a different part of the airport overnight. So the IRS is basically asking us if we would like to confirm those coordinates. By entering the GPS coordinates a second time, our IRS aligned and we were able to carry on.

Most modern if not all modern aircraft use an IRS (reference system) vs INS (navigation system). The INS used to do all the navigation for you before GPS and was susceptible to position shift the longer a flight went. Today, the IRS aligns before flight (using a GPS position) and then feeds the position to the FMC for the FMC to do the navigating. It’s amazing how accurate flying on GPS is these days.

 

[flyer89]

Does moving the aircraft with the IRS’s off have any effect on them? For example turning them off after a flight and the aircraft then being towed to a maintenance hangar.

 

[AviatorInsight]

Does moving the aircraft with the IRS’s off have any effect on them? For example turning them off after a flight and the aircraft then being towed to a maintenance hangar.

The last flight will turn the IRS off. So when the aircraft gets moved to its new position and the IRS is turned on again, it’ll remember the last position it was at. If it’s within a reasonable distance then it’ll accept the new position without any errors. However if it doesn’t agree, then it’ll make us think twice and confirm that the new coordinates are correct.

 

[flyer89]

New roster out now....

Out of interest is HK a senior route on the 380? I assume you don’t fly it because you don’t want to and/or you’re Melbourne based?

 

[jb747]

1.5 tonnes? Somewhere between not much and none at all. That may have been all they could get on because the aircraft out of LAX are always very near max take off weight.

 

[jb747]

The Melbourne base feels quite unloved at the moment, as, having lost the London service, all we now have are LA and Singapore. We'd hoped for a small share of the Singapore-London, but all of them went to the Sydney base.

HK is totally Sydney.

 

[jb747]

My question now, @jb747 , is the Medlink service available to a crew in the very far reaches of the Antarctic Ocean on QF28? Is there a Sat-Link? or other comm device to enable a medical decision/diagnosis?

I used to make a point of not flying down near Antartica, so I've never had cause to use the sat comm down there. I'd expect it to work most of the time, although there are times (even far further north), where you do lose the satellite links. Mostly they reappear within a few minutes.

If voice didn't work, you could certainly try sending a message via the data system...just type up the details and send it. They use a pro forma, so the chances are that you'd get most of the important questions on the first go. Just a bit time consuming.