Ask The Pilot

[Ansett]

I don't think you'll see it on the Airbus. They seem happy enough with the large winglets on the A320 NEO. I wouldn't even be surprised if there is an element of turning a sow's ear into a silk purse, in that the 737 wing design is basically ancient.

What about the A330 wings aren't they an ancient design too?

 

[jb747]

What about the A330 wings aren't they an ancient design too?

The 737 first appeared in 1968, whilst the A320 is a whole generation later from 1988 (and the 330 is even later). They've both had tweaks, but the 737 family is long overdue for total replacement. I suspect a lot of people wish the 757 line were still open.

 

[Flashback]

We had issues flying into GIB yesterday due to stormy conditions and the plane being outside operating limits as a result, when we arrived at the airport 4 hours later (from AGP by bus) we actually drove over the runway at which point I noticed that a) it's very exposed b) it's very short. Is it likely that cross winds were the reason for not being able to land there?

 

[jb747]

We had issues flying into GIB yesterday due to stormy conditions and the plane being outside operating limits as a result, when we arrived at the airport 4 hours later (from AGP by bus) we actually drove over the runway at which point I noticed that a) it's very exposed b) it's very short. Is it likely that cross winds were the reason for not being able to land there?

Had to work out where you were first. Gibraltar and Malaga.

Gibraltar is short. About the same length as Wellington. Not a place to muck about. I have no idea what the weather is like there normally, but the forecasts for yesterday included thunderstorms. So that can give you a dangerous mix of variable, strong winds, heavy rain and downdrafts. I expect the thunderstorms were the cause of the diversion, not necessarily crosswinds.

 

[Quickstatus]

Whats the windspeed in the video - see link:

Some windsocks have stripes.

The totally off-topic thread

 

[AviatorInsight]

Whats the windspeed in the video - see link:

Some windsocks have stripes.

The totally off-topic thread

There's always been a bit of a debate about this. It's hard to find a reference at the moment, but my understanding is:

White = Primary (horizontal is 30kts)
Yellow = Secondary (horizontal is 15kts)
Striped = horizontal is 15kts. The stripes indicate windspeed at 3,6,9,12 and 15kts.
Windsock gone = Cyclone

So from the video I'd say averaging windspeed is 20-30kts.

 

[jb747]

And don't forget, that if it isn't there, then there's a cyclone. And if it's wet, then it's raining.

To be honest, they don't get used to judge wind strength any more. There's much more accurate wind from either the tower or ATIS, and for some performance calculations, we do need accurate figures. But, they still give a good indication of direction, especially if the wind is moving about a bit.

 

[Quickstatus]

..And if it's wet, then it's raining.

Learn something new everyday!!

 

[Pvcmenace]

And then when its wrapped around the pole, look at the grass or trees.

 

[Captain Halliday]

What are the flight planning implications, if any, during long periods of poor weather at reasonably isolated airfields?

For example while DRW is technically open, all five Australian carriers suspended flights around 3pm today until Sunday due to TC Marcus. Given that SYD/BNE/MEL-DPS all typically have DRW as their alternate and those 738’s are operating near the limit of their range for those sectors, will it make a difference?

For aircraft with ETOPS of 120 or more I guess, CNS, ASP, BME and even ISA all come into play, but that’s no good without the necessary fuel.

 

[RobYg]

And then when its wrapped around the pole, look at the grass or trees.

On a gliding field, if it's pointing up vertically it's showing a damn good thermal.

 

[jb747]

What are the flight planning implications, if any, during long periods of poor weather at reasonably isolated airfields?

Declared isolation airports (such as Tahiti) have specific holding fuel requirements, above what would normally be required.

For example while DRW is technically open, all five Australian carriers suspended flights around 3pm today until Sunday due to TC Marcus. Given that SYD/BNE/MEL-DPS all typically have DRW as their alternate and those 738’s are operating near the limit of their range for those sectors, will it make a difference?

For aircraft with ETOPS of 120 or more I guess, CNS, ASP, BME and even ISA all come into play, but that’s no good without the necessary fuel.

I would be extremely surprised if Darwin is ever considered as an alternate for Bali. It's in the order of 800 nm away.

Firstly, many, and probably most, flights DO NOT have any alternate to destination. That means that on arrival they do not necessary have the fuel to go anywhere else. In the extreme case, as long as you finished the landing roll, with an amount of fuel equal to 30 minutes of holding, TO DRY TANKS, then you'd be legal.

During the flight, a twin will need to be able to go somewhere, flying at whatever speed has been chosen for the ETOPS calculations, within the time limit for that type. It will be calculated engine out, and at a ground speed of around 400 knots. If you were flying past Darwin, and it was not suitable, places like Mt Isa, RAAF Tindal, Derby, Broome, Learmonth, would all enter consideration.

At the destination end, Surabaya, Banjarmasin, Kupang, and probably many other Indonesian runways could be considered.

 

[andmiz]

It's one of those Australian rules which isn't replicated elsewhere in the world.. It's common for airlines overseas to be required to carry alternate fuel regardless of the weather at the destination. This rule has caught out some Australian operators (such as the emergency landings made at YMIA a few years back).
For instance, we consider Perth to be an 'island', just as you would Tahiti. There's no suitable aerodromes in the area so we carry 2 hours of holding fuel in case of unforecast weather conditions, or carry Adelaide as an alternate.
We can use our alternate fuel to ensure landing at our destination, but it needs to meet a strict set of criteria and assure landing.

 

[jb747]

It's one of those Australian rules which isn't replicated elsewhere in the world.. It's common for airlines overseas to be required to carry alternate fuel regardless of the weather at the destination. This rule has caught out some Australian operators (such as the emergency landings made at YMIA a few years back).

I think that was more a case of unforecast fog at the alternate. The logic of diverting away from a decent airport, albeit with one without CAT II/III, to one with only non precision approaches is suspect...but equally Australian. And silly.

For instance, we consider Perth to be an 'island', just as you would Tahiti. There's no suitable aerodromes in the area so we carry 2 hours of holding fuel in case of unforecast weather conditions, or carry Adelaide as an alternate.
We can use our alternate fuel to ensure landing at our destination, but it needs to meet a strict set of criteria and assure landing.

Perth tends to be a place where people are at least wary. I heard an aircraft from your part of the world declare a mayday due low fuel only a few weeks ago...at Dubai. I'm sure he would have loved another 2 hours of fuel.

 

[Cheatah]

For instance, we consider Perth to be an 'island', just as you would Tahiti. There's no suitable aerodromes in the area so we carry 2 hours of holding fuel in case of unforecast weather conditions, or carry Adelaide as an alternate.

So for those airlines operating to Perth, who do not carry enough fuel for an alternate operate with a significant competitive advantage ?

Given alternates can be required not just due to weather conditions (i.e. aircraft blocking runway, or in the case of Perth - both runways), its quite a risk no?

 

[jb747]

So for those airlines operating to Perth, who do not carry enough fuel for an alternate operate with a significant competitive advantage ?

Perth probably isn't the place to be considering. Most people are wary of the place, and carry some sort of options.

Given alternates can be required not just due to weather conditions (i.e. aircraft blocking runway, or in the case of Perth - both runways), its quite a risk no?

Ah, the blocking the runway scenario. Quite honestly, aviation is all about risks, and their management. If you covered every base, then no flight would ever depart. In the blocked runway case, in most cases you'd still be able to land on the taxiway, or even on the remaining runway. Max braking is very effective.

The rules for all operations state that you must, at all times in the flight, be able to suffer a depressurisation, descend to 14,000/10,000 feet, and then fly to an airport at which the weather is better than the approach minimum, and to then arrive with no less than 30 minutes of fuel at the end of the landing roll, i.e. not much. If you simply add a simultaneous engine failure to the scenario, which is, after all, a likely cause of the depressurisation in the first place...there are no rules to help. The fuel required could easily exceed the fuel available. The risk is low, so it's accepted. The risk of an oxygen bottle exploding was so low that it had never been considered, and yet it happened. You have to accept some risk, or no flights would happen.

 

[AviatorInsight]

So for those airlines operating to Perth, who do not carry enough fuel for an alternate operate with a significant competitive advantage ?

Given alternates can be required not just due to weather conditions (i.e. aircraft blocking runway, or in the case of Perth - both runways), its quite a risk no?

On the B737 in Australia we're very lucky. An alternate is always usually down the road. YGEL, YABA, and even YESP can be within reach. There's very little penalty for carrying the extra fuel, so I'll always take an alternate and not just for PER no matter what the forecast says.

Checks love asking the old aircraft blocking the runway scenario and some give me a weird look when I tell them that if push came to shove I'd go for a taxiway or the remaining runway as JB stated above. The thing is to always have a way out.

 

[Quickstatus]

Does The 737-800 ever need max fuel to do a transcontinental east to west?

 

[AviatorInsight]

Does The 737-800 ever need max fuel to do a transcontinental east to west?

I've never had to go anywhere near it. About 5T below max fuel capacity (20.5T) is normal and thats with carrying an alternate.

 

[Major]

I've never had to go anywhere near it. About 5T below max fuel capacity (20.5T) is normal and thats with carrying an alternate.

I assume from your answer that domestically you refer to tons when talking fuel. With us gallons, kg's, llb's as well as tons there is room for mistakes (Gimli glider comes to mind).

Is there a standard fuel unit of measurement and referral for Australian flights and do re fuelers use the same terms ?