Ask The Pilot

[Quickstatus]

Would appreciate an aviator comment:
Why does an ETOPS capable aircraft and airline operate a non ETOPS routing on an otherwise ETOPS route?

VH-QPA QF61 BNE-NRT 14May2017 and NRT-BNE as QF62D on 15May2017?.



Edit: seems to have travelled an extra 2600km and taken 11.3 hours . Usually the FA time northis about 8.75 hrs)

I don't think this is a favourable winds scenario? As the usual routing is South to north ,or to mitigate unfavourable winds?

 

[andmiz]

Would appreciate an aviator comment:
Why does an ETOPS capable aircraft and airline operate a non ETOPS routing on an otherwise ETOPS route?

Without researching into specifics of weather and the route for that day, there's a quick answer.

It could have easily been issues with volcanic ash over that part of the world, an nominated EDTO airport which was not suitable for any EDTO diversion, or an aircraft defect. JB might be able to check historical QF flight plans to see what the cause was. Otherwise he's got a spot of 330 time (?) and could otherwise explain what defects apply to EDTO.

 

[Quickstatus]

As far as I can see GUM was not closed on 14/15May. B777 like KA111 was operating ICN-GUM
BNE-NRT most direct routing is capable with ETOPS approval >120 min according to GCMap

 

[jb747]

If the QF A380 has a different version of the Trent900, is the version recognised by the Flight computers and therefore the differences in performance automatically accounted for in the ssoftware?.

I'd have to ask one of the engineers, but I'm not sure that there actually is any physical difference. As the engines are all on power to the hour (I expect that's the case for all of the operators), the difference may be as little as a software code in the FACEC/EEC, and a greater rental payment. In any event, the EEC would know the engine model, and would apply appropriate limits.

Does using a lower thrust version affect takeoff and range performance materially?

Max thrust affects take off performance. Full charge is most commonly used off 24L in LA. Use of TOGA and the shorter runway generally saves us lots of time. We could almost always go from 25L with a substantial derate. Other than that you'll see it used at max weight take offs on extremely hot days. There's no hard and fast rule as to how much weight you'd lose if you rolled the performance of the engines back to (say) 70,000 lbs. On some days you could still carry the full 569 tonnes. LA's operation would become more time consuming, as you'd pretty well always need 25L, with its long taxi. If you lost 5 tonnes of weight, that would cost you about 200 miles.

Fuel consumption could actually improve a little, if the reduction in thrust means that you are slightly lighter. Otherwise, the consumption would be the same at any given weight. TO/GA has no relevance to cruise flight.

 

[mjt57]

Yesterday we flew home LAX-MEL The route took us crossing the coast north of Brisbane and down to Melbourne west of Canberra.

This was with United on one of its Dreamliners (and I use the word "Dream" in Dreamliner loosely).

The year before we flew home, LAX-MEL on Virgin Oz and a B777. That route had us crossing the coast south of Sydney, crossing over Thredbo, etc, and into Melbourne from the east.

Both flights got us in early morning.

Why the different routes? Is it weather dependant, perhaps? In both cases it was late May and weather typical for the season - cold, overcast, no rain.

Anyway, political comment - I dread the thought of flying QF to the UK on one of these 787s. Ok if you're in business or better, but damned miserable in plebsville.

 

[AviatorInsight]

Yesterday we flew home LAX-MEL The route took us crossing the coast north of Brisbane and down to Melbourne west of Canberra.

This was with United on one of its Dreamliners (and I use the word "Dream" in Dreamliner loosely).

The year before we flew home, LAX-MEL on Virgin Oz and a B777. That route had us crossing the coast south of Sydney, crossing over Thredbo, etc, and into Melbourne from the east.

Both flights got us in early morning.

Why the different routes? Is it weather dependant, perhaps? In both cases it was late May and weather typical for the season - cold, overcast, no rain.

Anyway, political comment - I dread the thought of flying QF to the UK on one of these 787s. Ok if you're in business or better, but damned miserable in plebsville.

The routing changes daily. The software tries to give the fastest flight time using the winds available and so doesn't always follow the great circle track. In some cases, dispatch will change the routing from the software to avoid us flying through tropical cyclones or volcanic ash.

On some flights I've been as far north as the Marshall Islands and as far south as Tahiti.

It always sucks flying a northerly track into MEL only to see my house sailing past in Sydney, knowing I've gotta come back again after the flight but that's life.

 

[mjt57]

The routing changes daily. The software tries to give the fastest flight time using the winds available

On the in seat flight map at times it said that we had 90 mph headwinds. Is this possible?

It always sucks flying a northerly track into MEL only to see my house sailing past in Sydney, knowing I've gotta come back again after the flight but that's life.

Same for the easterly route into MEL for us. I could see my workplace from the aircraft (yes, it's that big) and wishing that they could land and drop me off, rather than to face 2hr drive home.

 

[AviatorInsight]

On the in seat flight map at times it said that we had 90 mph headwinds. Is this possible?

Absolutely! 90mph is only about 78kts. Usually approaching the east coast of Australia at this time of the year it's not uncommon to have winds up to 120kts right on the nose, thanks to the higher level jetstreams. By that stage we're already at our final cruising level.

 

[docjames]

Absolutely! 90mph is only about 78kts. Usually approaching the east coast of Australia at this time of the year it's not uncommon to have winds up to 120kts right on the nose, thanks to the higher level jetstreams. By that stage we're already at our final cruising level.

Presumably the fuel burn penalty and/or the winds at lower levels are worse (hence no "stepped" descent)?

 

[AviatorInsight]

Presumably the fuel burn penalty and/or the winds at lower levels are worse (hence no "stepped" descent)?

It's more the fuel burn at the lower levels towards the end of the flight that is the issue. The winds are usually stronger the higher up you go but it's not always the case. There has been at times noted on the flight plan for a stepped descent, but this is usually so close to the top of descent point that it really negates any fuel savings.

Sometimes the winds leaving LA have been so strong (and reported turbulence associated with it) leaving LA, that our first level was FL230.

 

[jb747]

The average wind for the QF94 that arrived yesterday was a 38 knot headwind. Highest I can recall for the flight was about 120 knots. The strongest I've ever seen is well over 200 knots.

The FMCs constantly calculate the optimum flight level. Generally this is about 2,000 feet less than the maximum, but it will vary if you have winds and temperatures loaded for alternative levels. When we go into the performance application (on the laptops) to look at cruise data, it will also show information on alternative levels. This is presented in the form of "break even" data. For example, break even for a level 2,000' below optimum may require the wind component to be 10 knots better. Mostly, unless you're considering getting into, or out of, a jet stream, you'll just go with the optimum level.

Out of LA, especially on the route towards HNL, the headwinds are strong, but even more important, they're often quite bumpy. The 380 can generally climb higher than the 747/777s at the early stages of the flight, and can often get high enough to be out of the worst of it.

It's unusual to have the flight plan include lower levels, but we may choose to ask for lower if it gets rough. The cost of going lower on long flights generally exceeds the cost of living with the wind.

There are strategic reasons for taking a level too. For instance, you might choose to climb early if clearances are hard to get later, or because you expect that other traffic may block you.

 

[mjt57]

The average wind for the QF94 that arrived yesterday was a 38 knot headwind. Highest I can recall for the flight was about 120 knots. The strongest I've ever seen is well over 200 knots.

Wow, that's a headwind. Sort of like what I experience whenever I want to take the bike for a ride, in any direction...

Seriously, though, at 200kts what would your IAS be? Or ground speed, even? How much power is required to maintain a stable envelope or whatever it is that you guys call it?

Finally, how many bods are required for the LAX-MEL route? UAL on the 787 had 4 FOs and the captain.

 

[jb747]

Wow, that's a headwind. Sort of like what I experience whenever I want to take the bike for a ride, in any direction...

Seriously, though, at 200kts what would your IAS be? Or ground speed, even? How much power is required to maintain a stable envelope or whatever it is that you guys call it?

IAS and power are exactly the same as usual. We fly in an air mass....the fact that that air mass is moving as well affects the ground speed and track, but has no direct effect on the aircraft. So, IAS will be around 290 kt, and TAS will be about 490 kt. Ground speed is the result of applying the wind component to the TAS.

Finally, how many bods are required for the LAX-MEL route? UAL on the 787 had 4 FOs and the captain.

It's operated with a 4 man crew. 1 Captain, 1 FO, and 2 SOs.

 

[Quickstatus]

IAS and power are exactly the same as usual. We fly in an air mass....the fact that that air mass is moving as well affects the ground speed and track, but has no direct effect on the aircraft. So, IAS will be around 290 kt, and TAS will be about 490 kt.

Therefore an aircraft's stall speed is at the same IAS irrespective of altitude?

....
#11101?

 

[RooFlyer]

Pilots, you may have seen discussion on another thread about the recent MH incident at MEL, and what the security forces did and didn't do (such as get the passengers off sooner rather than later).

This may fall into the category of commenting on security, and if so understandably won't be answered (but I hope maybe in generalities), but:

If a plane has landed, and the pilot and crew are not incapacitated or obviously under duress and can communicate that to the outside, does the captain still technically have 'control' of the aircraft, in Australia? If security authorities wish to board either 'peacefully' or with forceful intent do they strictly need the captains OK? Or can some security bod effectively declare 'force majeure' and do what they wish, irrespective of what the captain may actually say, or want?

 

[jb747]

Therefore an aircraft's stall speed is at the same IAS irrespective of altitude?

The comment above actually related to wind, and the relationship between TAS and GS.

The stall speed is similar at all altitudes. The stall angle of attack is reduced by mach effects, so it does increase the speed (IAS), but magnitude of the change isn't great.

 

[jb747]

Pilots, you may have seen discussion on another thread about the recent MH incident at MEL, and what the security forces did and didn't do (such as get the passengers off sooner rather than later).

This may fall into the category of commenting on security, and if so understandably won't be answered (but I hope maybe in generalities), but:

If a plane has landed, and the pilot and crew are not incapacitated or obviously under duress and can communicate that to the outside, does the captain still technically have 'control' of the aircraft, in Australia? If security authorities wish to board either 'peacefully' or with forceful intent do they strictly need the captains OK? Or can some security bod effectively declare 'force majeure' and do what they wish, irrespective of what the captain may actually say, or want?

Nobody is going to give you much of a discussion about security.

 

[RooFlyer]

Understand, thanks.

 

[Melburnian1]

Nobody is going to give you much of a discussion about security.

Understand, but at a public level, are there likely to be any concerns expressed through the media by the air pilots federation, the Board of Airline Representatives in Australia or various unions or employee associations representing cabin crew?

For instance, 'The Australian' has its Friday couple of pages (occasionally just a single page) on aviation in its business section, usually after legal affairs. There are also specialist aviation industry publications.

Or with these matters that have played out so much in the media, do all those organisations have a huge preference for any discussions to be in camera?

 

[jb747]

Understand, but at a public level, are there likely to be any concerns expressed through the media by the air pilots federation, the Board of Airline Representatives in Australia or various unions or employee associations representing cabin crew?

As I am not a member of any of these organisations, I have no idea what they are doing, or are likely to do.

But, as a generalisation, just because the media expresses a concern, it does not mean it came from anyone in particular.....