Ask The Pilot

[jb747]

You'll have seen the report on the VA 737 that had to offload pax due to no wind/ takeoff performance at Wellington.

In that situation, what is the decision process around who/what gets offloaded?

Cargo may have high net worth to the airline so shifting that off may not always be possible. How is the decision taken, is it entirely up to the captain or is it airline operations, do they go for minimum pax affected (but on a major scale), or would offloading sufficient baggage affect more pax but less significantly (delayed bag but still get to destination)? Would carry on only pax be preferred due to not needing to remove bags from hold, or not really a consideration? Would the number of offloaded pax vary depending on how much checked luggage each had?

I've got to admit that I was a little surprised by the gist of the articles. I've only ever operated the 767 to Wellington, and I guess take off performance was never an issue in that aircraft, but I wouldn't have expected it to be in a 737 either. The wind in Wellington is often purely crosswind, so it offers no help anyway.

Cargo can be valuable for sure, but I'm not sure that Wellington exports much....

Anyway, I've never been in the situation of offloading passengers (for weight). I've had to lose weight before, but I've done so by directing that a pallet be removed. I've never asked what was on the pallet, and the company has never queried it.

In the case in question, I expect the offload priority would be inversely proportional to the fare.....

 

[markis10]

I've got to admit that I was a little surprised by the gist of the articles. I've only ever operated the 767 to Wellington, and I guess take off performance was never an issue in that aircraft, but I wouldn't have expected it to be in a 737 either. The wind in Wellington is often purely crosswind, so it offers no help anyway.

Cargo can be valuable for sure, but I'm not sure that Wellington exports much....

Anyway, I've never been in the situation of offloading passengers (for weight). I've had to lose weight before, but I've done so by directing that a pallet be removed. I've never asked what was on the pallet, and the company has never queried it.

In the case in question, I expect the offload priority would be inversely proportional to the fare.....

Seriously doubt any cargo would be loaded on the first flight out of a Monday morning, any residual freight from business hours last week would have been already shifted on earlier flights or the overnight freighters that ply the ditch. VA carry very little freight across the ditch looking at the BITRE figures so I suspect the freighters carry almost all of it.

 

[jb747]

Seriously doubt any cargo would be loaded on the first flight out of a Monday morning, any residual freight from business hours last week would have been already shifted on earlier flights or the overnight freighters that ply the ditch. VA carry very little freight across the ditch looking at the BITRE figures so I suspect the freighters carry almost all of it.

So why would they be so heavy? I suspect there is more to the story than we have.

 

[markis10]

So why would they be so heavy? I suspect there is more to the story than we have.

Am sure there is given the source, it was not like Brisbane was expecting bad weather for its arrival.

 

[petercr]

Maybe because of the potential need to divert at this end if the conditions were unfavourable? (I guess heading that way there's a few more airports closer together than over this side)

Or it could be all the chocolate fush, pineapple lumps and L&P that get exported to our side of the ditch. ?.


Edit: Markis- the article said Saturday afternoon (ex Wellington?) and the weather was fine here in the arvo albeit with a NW breeze so doubt it was that issue...

 

[ChrisGibbs]

JB747 - last week I was on QF127 (744) to Hong Kong. Standing near Door L1 while the aerobridge was being docked I struck up a conversation with the CSM who I'd met on a number of flights previously. We spoke about an inadvertent slide deployment on a QF767 back in May. I did some digging around on the net and saw that an inadvertent slide deployment can cost an airline about $20K per incident (not including any downtime for the aircraft). The annual cost in North America alone for inadvertent slide deployment is about $20m per year (I assume this would include downtime for the aircraft as 1,000 incidents per year sounds high).

The question I have is why are the aircraft doors opened from the outside (apart from the 737). Is it to disarm the slide even if the doors are still armed? Can you shed any light on whether the cabin crew that operate the 737 / 767 / 744 / A330 / A380 have different procedures for opening doors?

Thanks in advance.

 

[jb747]

JB747 - last week I was on QF127 (744) to Hong Kong. Standing near Door L1 while the aerobridge was being docked I struck up a conversation with the CSM who I'd met on a number of flights previously. We spoke about an inadvertent slide deployment on a QF767 back in May. I did some digging around on the net and saw that an inadvertent slide deployment can cost an airline about $20K per incident (not including any downtime for the aircraft). The annual cost in North America alone for inadvertent slide deployment is about $20m per year (I assume this would include downtime for the aircraft as 1,000 incidents per year sounds high).

It doesn't sound all that high to me. 1,000 is a big number, but there are a lot of aircraft in the USA, and a vast number of 'door opening' cycles every day.

The question I have is why are the aircraft doors opened from the outside (apart from the 737). Is it to disarm the slide even if the doors are still armed? Can you shed any light on whether the cabin crew that operate the 737 / 767 / 744 / A330 / A380 have different procedures for opening doors?

Obviously I can only speak for the aircraft that I've flown, but yes, they're opened from the outside because they always disarm when opened on that side. A few years back I had a rather chastened CSM approach me after a flight to say that one door had been opened whilst still armed. It happens. People are human, and this is a nice last safety step.

 

[Melburnian1]

Newspaper reports indicate that at Wellington, VA contractors or staff followed the practice of 'asking' for volunteers to be offloaded: meals plus an hotel overnight followed. There hasn't been any suggestion that some passengers were 'involuntarily bumped off the plane', if that's the correct terminology. The reports imply that VA struggled to get sufficient 'volunteers' as they accepted the offer in ones and twos (which makes sense, since all that means is that there were few or no family groups, sporting clubs and so on travelling.

 

[el_rooto]

What is the average burn rate of fuel per hour on a 744 and 380?

 

[jb747]

Newspaper reports indicate that at Wellington, VA contractors or staff followed the practice of 'asking' for volunteers to be offloaded: meals plus an hotel overnight followed. There hasn't been any suggestion that some passengers were 'involuntarily bumped off the plane', if that's the correct terminology. The reports imply that VA struggled to get sufficient 'volunteers' as they accepted the offer in ones and twos (which makes sense, since all that means is that there were few or no family groups, sporting clubs and so on travelling.

When I've seen this sort of thing done overseas, it normally comes with accommodation, meals and a quite reasonable number of Euros/US dollars per day. I can't imagine why anyone would do it for free, or just costs.

The point Markis and I were working around was the 'why'. As there's unlikely to be any cargo, and Brisbane didn't have any outlandish weather/fuel requirements, then why was the aircraft so heavy that it became performance limited without any headwind. Planning should not be taking wind into account when they sell the seats...as often as not Wellington is very windy, but it's all crosswind, so that does not help at all with the performance calculations. If they NEED the wind to become airborne, then offloads should be reasonably common...unless it's rarely got a decent pax load.

 

[jb747]

What is the average burn rate of fuel per hour on a 744 and 380?

It varies a lot during the flight, starting off at about 16,000 kgs/hour (13,000 kgs/hour), and then falling as you climb and the weight decreases, to about 10,000 kg/hour (8,500 kgs/hour). If you worked on an average of 13 and 11 tonnes you wouldn't be far out.

 

[markis10]

The point Markis and I were working around was the 'why'. As there's unlikely to be any cargo, and Brisbane didn't have any outlandish weather/fuel requirements, then why was the aircraft so heavy that it became performance limited without any headwind. Planning should not be taking wind into account when they sell the seats...as often as not Wellington is very windy, but it's all crosswind, so that does not help at all with the performance calculations. If they NEED the wind to become airborne, then offloads should be reasonably common...unless it's rarely got a decent pax load.

Agree, although for some reason I was thinking it was Monday AM, not Saturday, so more likely to have some freight, and at the same time an easier decision to take it off and put it on a later service to still be there for business hours Monday. Without first hand accounts from people who have more knowledge than the average jurno, no sure we are closer to the truth.

 

[CaviAck]

When I've seen this sort of thing done overseas, it normally comes with accommodation, meals and a quite reasonable number of Euros/US dollars per day. I can't imagine why anyone would do it for free, or just costs.

The point Markis and I were working around was the 'why'. As there's unlikely to be any cargo, and Brisbane didn't have any outlandish weather/fuel requirements, then why was the aircraft so heavy that it became performance limited without any headwind. Planning should not be taking wind into account when they sell the seats...as often as not Wellington is very windy, but it's all crosswind, so that does not help at all with the performance calculations. If they NEED the wind to become airborne, then offloads should be reasonably common...unless it's rarely got a decent pax load.

Is it possible they were flying with derated engines and didn't plan accordingly? (Or am I thinking of the wrong term...) That was one of the tales I got from one of the pilots when this happened to me on VA...

 

[el_rooto]

User error...

 

[giantkingsquid]

It varies a lot during the flight, starting off at about 16,000 kgs/hour (13,000 kgs/hour), and then falling as you climb and the weight decreases, to about 10,000 kg/hour (8,500 kgs/hour). If you worked on an average of 13 and 11 tonnes you wouldn't be far out.

Is that just because of more modern engines in the Airbus? Because to my eye the 747 looks more slippery than the A380. Either way, its a lot bigger difference than I thought it would be!

p.s. You wouldn't happen to know the coefficient of drag for either aircraft in the cruise?

 

[MEL_Traveller]

It doesn't sound all that high to me. 1,000 is a big number, but there are a lot of aircraft in the USA, and a vast number of 'door opening' cycles every day.



Obviously I can only speak for the aircraft that I've flown, but yes, they're opened from the outside because they always disarm when opened on that side. A few years back I had a rather chastened CSM approach me after a flight to say that one door had been opened whilst still armed. It happens. People are human, and this is a nice last safety step.

does the A380 have a door challenge procedure?

if it is possible to leave a door armed on arrival, is it also possible for a door to remain disarmed after departure? (assuming it is functioning normally and supposed to be armed)

 

[sjd]

Experienced a landing at CNS yesterday in a QF B738 that rolled quite a number of times in both directions during the last part of the descent and even as we touched down. Having flown at least 1 to 2 flights weekly on these birds in the last two years, mostly to and from CNS, (still a tiny fraction of all actual flights) I've not experienced a flight with that much rolling going on at landing, (there is ususally a little bit going on). Was wondering if you could, in your wisdom, jb747, shed some light?

 

[straitman]

Experienced a landing at CNS yesterday in a QF B738 that rolled quite a number of times in both directions during the last part of the descent and even as we touched down. Having flown at least 1 to 2 flights weekly on these birds in the last two years, mostly to and from CNS, (still a tiny fraction of all actual flights) I've not experienced a flight with that much rolling going on at landing, (there is ususally a little bit going on). Was wondering if you could, in your wisdom, jb747, shed some light?

sjd,

Do you have any idea what the wind was :?:

A cross wind form off the hills would create problems from both at wind and turbulence created.

 

[sjd]

sjd,

Do you have any idea what the wind was :?:

A cross wind form off the hills would create problems from both at wind and turbulence created.

According to BOM wind was ESE gusting to 30km/h at the time.

 

[jb747]

Is that just because of more modern engines in the Airbus? Because to my eye the 747 looks more slippery than the A380. Either way, its a lot bigger difference than I thought it would be!

p.s. You wouldn't happen to know the coefficient of drag for either aircraft in the cruise?

The figures in brackets are the 747. The 380 is always worse than the -400, which is okay as long as your pax load is also appreciably larger. I doubt that it's anywhere near as 'green' as claimed by the maker though...unless you happen to paint it that colour.