Ask The Pilot

[uzza]

I hope not. I certainly would not help. It's ancient history now.

Anyway, you can't make a show from "It went bang, we descended, we landed." Done.

Thanks JB, I can appreciate your view on the subject!

Thanks also for this thread, it's a great read - particularly coming from such an expert source

 

[day-heg]

JB, I think this might have missed a few days ago... would be interested in your thoughts, and that of other pilots of the forum.
Cheers.

On an entirely separate note JB - I was wondering if you keep an 'old fashioned' log book for all your flights, or if you had a digital solution of some sort? Or both? Are there any CASA regs that mandate you to keep paper records? Apologies if this has been asked already... I did a quick search but nothing came up.

 

[jb747]

JB, I think this might have missed a few days ago... would be interested in your thoughts, and that of other pilots of the forum.
Cheers.

I've seen people using iPads and their ilk to record flights, but I suspect the majority just use the records that the company keeps. I use an Excel spreadsheet.

 

[Sprucegoose]

I hope not. I certainly would not help. It's ancient history now.

Anyway, you can't make a show from "It went bang, we descended, we landed." Done.

JB appreciate your point however from the incident and the investigations what were the learnings and as a result were any SOP's changed, within QF or the industry?

 

[QFflyermelbourne]

Hi JB,

Up thread a little when referring to late comers and so forth being allocated 100Kg: in this day and age of larger folks and also the propensity of a lot of people to overload their hand luggage and probably bring a lot more than the 7kg they are told they are allowed, how much would it take for your figures to start to impact take off and climb out performance? I'm thinking what if there are 20 people for instance you have allocated 100kg to but in some hypothetical they were all carrying 120kg. What is the margin here and how does it differ between the 380 for instance and say a 737-800?

Thanks...

 

[alieninperth]

Wasn't this scenario (average weight used was less than actual weight) a contributing factor, if not the factor, that caused a plane load of US soldiers to crash on take off? I seem to remember that the pilots used average weight of 100kg when the actual average weight would have been about 120-140kg with packs and equipment.

 

[medhead]

Wasn't this scenario (average weight used was less than actual weight) a contributing factor, if not the factor, that caused a plane load of US soldiers to crash on take off? I seem to remember that the pilots used average weight of 100kg when the actual average weight would have been about 120-140kg with packs and equipment.

Not sure about any soldiers. But there is the Air Midwest Flight 5481 crash that was partially attributed to using an incorrect passenger weight estimate. Probably critical for a small number of passengers, such as in that case. However, statistics tell us that once you have a sample over a certain size (100+) the average will be a very good estimate. Possibly the failure in that case would be using the average for the general population for a different group of people (soldiers with equipment)

 

[mannej]

Not sure about any soldiers. But there is the Air Midwest Flight 5481 crash that was partially attributed to using an incorrect passenger weight estimate. Probably critical for a small number of passengers, such as in that case. However, statistics tell us that once you have a sample over a certain size (100+) the average will be a very good estimate. Possibly the failure in that case would be using the average for the general population for a different group of people (soldiers with equipment)

Arrow Air 1285 is the accident being referred to.

Arrow Air Flight 1285 - Wikipedia, the free encyclopedia

 

[petercr]

JB, what factors and how in advance are potential diversions due to weather planned (if they can be 'planned') and what would they be taking into account?

Reason I ask is that according to Qantassource QF52 inbound was diverted to CNS on Monday morning due to 'weather' at BNE but the only weather from about 4am til after 9am was light rain showers... (my dogs decided they wanted to go out that early so I noticed what it was like outside). The BOM shows there was all of about 3mm recorded at BNE on Monday and there had been a thunder storm early the previous evening but would have been well off the coast by the time 5am rolled around. The diversion appears to have commenced about the time it was in the region of the NT/SA/QLD border.

thanks in advance..

 

[petercr]

Arrow Air 1285 is the accident being referred to.

Arrow Air Flight 1285 - Wikipedia, the free encyclopedia

Nope, medhead was correct... Arrow Air 1285 was due to icing on the wing upper surface (according to the majority of the NTSB board), Air Midwest 5481 was due to weight mis-calculation combined with incorrect maintenance.

Air Midwest Flight 5481 - Wikipedia, the free encyclopedia doesn't seem to mention any military pax on board

 

[straitman]

Without being seen to discourage discussion I must remind people of the specific rules of this thread.

From post #1.

As this is an "ask the pilot" thread, we ask that non-pilot members refrain from answering questions that have been directed to pilots until the pilots members have had a good opportunity to answer the question (i.e. at least 7 days). Posts contrary to this request or discussions that get too far off topic may be removed or moved to a more appropriate thread or forum so we can retain order and respect in this thread.

 

[mannej]

Nope, medhead was correct... Arrow Air 1285 was due to icing on the wing upper surface (according to the majority of the NTSB board), Air Midwest 5481 was due to weight mis-calculation combined with incorrect maintenance.

Air Midwest Flight 5481 - Wikipedia, the free encyclopedia doesn't seem to mention any military pax on board

You have your episodes mixed up, as Arrow Air refers to the military on board. Air Midwest was a combination of poor maintenance and an overweight aircraft.

 

[MEL_Traveller]

Without being seen to discourage discussion I must remind people of the specific rules of this thread.

From post #1. [/COLOR]

can we have a separate thread for issues raised on the 'ask the pilot' thread? there are often issues which warrant further discussion but no where to put it...

 

[NM]

can we have a separate thread for issues raised on the 'ask the pilot' thread? there are often issues which warrant further discussion but no where to put it...

Feel free to start a thread on any topic that is raised in this thread. Anyone can do that. You can link to a specific post/question raised here and and discussion can free-flow from anyone interested in contributing. Occasionally the mods will move posts from here into their own thread if it is clear that more general discussion is warranted. If its a question you have, then post it in the "Your Questions" forum. If its general discussion, the post it in the "Open Discussion" forum.

 

[jb747]

Up thread a little when referring to late comers and so forth being allocated 100Kg: in this day and age of larger folks and also the propensity of a lot of people to overload their hand luggage and probably bring a lot more than the 7kg they are told they are allowed, how much would it take for your figures to start to impact take off and climb out performance? I'm thinking what if there are 20 people for instance you have allocated 100kg to but in some hypothetical they were all carrying 120kg. What is the margin here and how does it differ between the 380 for instance and say a 737-800?

For every person who weighs in at 120 kgs, there's one at 80 kgs. The load sheet data does not use the average 100 kgs weight, but figures that vary with the route. Some nationalities are heavier than others, and that's catered for. But, at my level, I don't care about a few kgs difference, and the 100 kg number is more than good enough.

And yes, lots of cabin luggage is common, but if you look around, you'll see there are still many people who carry nothing, or next to nothing, into the cabin. In the very large samples that the airlines use, I don't think you'll find a great deal of error.

In any event, the sort of number you're talking about is very small in the scheme of things, so whilst it might be measurable as an increase in overall fuel burn, the effect on take off and climb performance is tiny.

 

[legroom]

Hi JB

Is there any truth in the oft-heard FA's request to "remain in your seats until seat belt signs are off before you could relocate to another empty seat of your choice" in the event of a relatively empty flight ?

This is often followed by the request that pax "move back to your original seats before landing".

It is often explained as "important" for load balancing etc....

As a layman, I doubt if that is true but remains open to further info from a professional.

Many thanks

 

[jb747]

JB, what factors and how in advance are potential diversions due to weather planned (if they can be 'planned') and what would they be taking into account?

Reason I ask is that according to Qantassource QF52 inbound was diverted to CNS on Monday morning due to 'weather' at BNE but the only weather from about 4am til after 9am was light rain showers... (my dogs decided they wanted to go out that early so I noticed what it was like outside). The BOM shows there was all of about 3mm recorded at BNE on Monday and there had been a thunder storm early the previous evening but would have been well off the coast by the time 5am rolled around. The diversion appears to have commenced about the time it was in the region of the NT/SA/QLD border.

It's a bit hard to say why one particular flight would have diverted without access to the flight plans, weather forecasts, and weather actuals that the crew used.

Firstly though, the weather that you see on the ground doesn't have much to do with it. If the TTF weather reports (trend type forecasts) include something of interest, then the crew must allow for that. If there is a possibility of fog, then you have to cater for that, whether or not the fog actually eventuates. And the same for thunderstorms or anything else that goes below the 'alternate criteria'. So, if, a couple of hours out, the TTF required an alternate (or extended holding), and the crew did not have that available to them, then they have no choice but to divert. And, as most flights don't arrive with fuel to divert to places that are hundreds of miles away from destination, that diversion will have to happen a long way out. Yes, if they'd continued the next TTF might have been ok, but it's only the one that is current at the decision point that is relevant.

Diversions can be planned a very long way out. Well before take off in fact. On a recent flight to Dubai the forecast had thunderstorms over the entire period of interest, so we would have had to carry an alternate all the way to touchdown. Given that we also needed extensive holding fuel, that wasn't easily possible. One way around it would have been to go as fast as possible, have a pre planned landing at some other point (Muscat would be one way to do it, but another would be to carry much less fuel to start with, and go via Perth). I actually chose a third option, and offloaded almost all of the cargo. On another trip, in the 767, we simply could not carry sufficient fuel out of Melbourne to arrive in HK with adequate alternate fuel (when the typhoon is around you might need to divert a long way). So we flew straight to Darwin, where they were waiting for us, and had us in and max fuel on board in about 20 minutes.

 

[jb747]

Is there any truth in the oft-heard FA's request to "remain in your seats until seat belt signs are off before you could relocate to another empty seat of your choice" in the event of a relatively empty flight ?

This is often followed by the request that pax "move back to your original seats before landing".

It is often explained as "important" for load balancing etc....

As a layman, I doubt if that is true but remains open to further info from a professional.

A year or so ago I was denied travel on a staff ticket. It was explained as be a loading issue. I knew the aircraft had many seats available, and so I checked. As it turned out, it was quite true. The aircraft was carrying some very heavy cargo, and the loadsheet required that a certain passenger section remain empty.

As implied in an answer about loading tolerances, a passenger or two being in the wrong seat makes little difference in a big aircraft. It becomes much more of an issue as the aircraft become smaller. But, in the large aircraft, and with a light load, you aren't talking about a couple of people moving. It could easily be dozens.

When the loadsheet is generated, it looks at the CofG over the entire flight. Obviously fuel is used, and that causes the CofG to move forward. The passenger and cargo loading is arranged so that the balance stays within the allowed limits at all of the fuel loadings that will be experienced on that flight. So, yes, you are being used as a human counterbalance, and you should be in the correct seat fore and aft. Laterally it makes little difference.

What happens if you go outside of the CofG limits? Well, too far aft, and the aircraft will initially become 'twitchy', and ultimately unflyable. A video of an extreme aft cg can be found here https://www.youtube.com/watch?v=uIjO0sKBDDw

Too far forward and you can run out of up elevator. So it might not rotate correctly on take off.....

 

[QF WP]

Two thousand likes in a thread is testament to the value we place on the information shared here by jb747 and others. We certainly have leant a lot

 

[Boris spatsky]

Hi JB

Is there any truth in the oft-heard FA's request to "remain in your seats until seat belt signs are off before you could relocate to another empty seat of your choice" in the event of a relatively empty flight ?

This is often followed by the request that pax "move back to your original seats before landing".

It is often explained as "important" for load balancing etc....

As a layman, I doubt if that is true but remains open to further info from a professional.

Many thanks

To add to JBs comments, i fly short haul domestic and we frequently do have issues with Centre of Gravity down to even 100 kgs. The other day out of Melbourne we had a very light load of pax and bags. We had to refuse two seat changes from the FAs as we were right on aft C of G, even with most of the pax seated fairly forward. The load sheet would have calculated out of C of G had they moved. In fact we were delayed as we had to move two pax backwards initially to meet the minimum number of pax in the emergency exit row due no shows.

On my aircraft, it becomes more of a problem with light loads, especially when coupled with minimum fuel and/or no cargo.