Ask The Pilot

[FlyboyAl]

JB. Today we came into Sydney on QF94. They needed to take on additional fuel due to the fog in Melbourne. That in itself was no drama, but it got me to thinking (sometimes a dangerous thing!).
What if there had been a hold up on the refueling, and what if the fog had lasted longer than expected in Mel?
What happens to the crew hours? That got me to thinking about what are the actual crew hours? Is it simple like a duty time of 16 hours? or more, or less? Or more complicated than that?
And like many others, THANKS HEAPS for this great thread

 

[Himeno]

What if there had been a hold up on the refueling, and what if the fog had lasted longer than expected in Mel?
What happens to the crew hours? That got me to thinking about what are the actual crew hours? Is it simple like a duty time of 16 hours? or more, or less? Or more complicated than that?

I had a similar experience. In Sep 2009, I was on QF32 which diverted to KUL with ATC holds and storms around SIN. Many other pax were worried about connections. I was more worried about crew hours. If the hours ran out, would we have been stuck in KUL until the crew had had enough rest for the 40 min flight down to SIN? Would we have been bussed down, put on other flights, new crew sent up from SIN?

 

[jb747]

JB. Today we came into Sydney on QF94. They needed to take on additional fuel due to the fog in Melbourne. That in itself was no drama, but it got me to thinking (sometimes a dangerous thing!).
What if there had been a hold up on the refueling, and what if the fog had lasted longer than expected in Mel?
What happens to the crew hours? That got me to thinking about what are the actual crew hours? Is it simple like a duty time of 16 hours? or more, or less? Or more complicated than that?

Crew hours are complicated. They vary with the number of crew, what sort of break you've had, how much flying you've done in the past week/month, and many other factors.

Keeping it simple though, the absolute limit is 20 hours of duty time. That will require an extension, which is granted solely at the crew members' discretion, so companies cannot plan on it. It's rare that is isn't granted though. LA-Melbourne has a planned duty of 17:20, so you have a couple of hours leeway. Dallas will be much tighter, with only about an hour spare. You cannot intentionally exceed the 20 hours. If that means a diversion, then so be it. As you were in Sydney, a hold up in refuelling would mean that they'd have called out the standby crew, and replaced all of the crew. Generally they have a good idea that it's going to happen, so the refuellers are ready, and the turn around can be surprisingly fast. If the fog lasted, then the original crew would have been displaced before departure from Sydney, but it's certainly not impossible that a second diversion could become necessary.

Even below the limiting hours, the pilots can 'pull the pin' if they feel too tired to continue. If you don't manage any sleep on the leg from LA, then you feel like death warmed over on arrival....and that's not a good time to be flying an aircraft.

 

[jb747]

I had a similar experience. In Sep 2009, I was on QF32 which diverted to KUL with ATC holds and storms around SIN. Many other pax were worried about connections. I was more worried about crew hours. If the hours ran out, would we have been stuck in KUL until the crew had had enough rest for the 40 min flight down to SIN? Would we have been bussed down, put on other flights, new crew sent up from SIN?

QF32 is quite likely to be a two pilot operation, which may have been under a couple of different sets of rules. For one, a flight time limit of 8 hours, with a (crew discretion) extension to 9 hours, or alternatively, a planned 8:30, but with no extensions at all. Last time I operated the 767 on similar flights, it was under the second rule. If a third pilot was carried, the times open out dramatically.

If the crew had run out of hours, and were operating under the second rule, then the next time they could fly would be at least 12 hours away (and it may be more, I don't have a copy of that rule at the moment). There would have been a crew in Singapore waiting for the aircraft, and they would have paxed to KL to pick it up. The original crew would drop out of the picture. Of course, limits would then come into play for the second crew, so it could actually end up requiring a third. It gets messy very fast.

 

[por930]

jb, I live on finals (close to the Gateway Bridge)for 01 at Brisbane. I often notice aircraft approaching 01 after reaching intersection Glenn(adjacent to Archerfield), then approaching down the ILS, what appears to be the larger the aircraft such as 744, A380 and even 767 approach lower than smaller aircraft such as 737 and A320 over my house. This is especially so in good VFR conditions. It is like the 'smaller' guys have more flexibility that the big guys. I just noticed several a/c 3 or 4 minutes apart while the 737 size were higher, the A380 and 767 were lower. The A380 was very quiet compared with the 744 and the 737..

 

[jb747]

jb, I live on finals (close to the Gateway Bridge)for 01 at Brisbane. I often notice aircraft approaching 01 after reaching intersection Glenn(adjacent to Archerfield), then approaching down the ILS, what appears to be the larger the aircraft such as 744, A380 and even 767 approach lower than smaller aircraft such as 737 and A320 over my house. This is especially so in good VFR conditions. It is like the 'smaller' guys have more flexibility that the big guys. I just noticed several a/c 3 or 4 minutes apart while the 737 size were higher, the A380 and 767 were lower. The A380 was very quiet compared with the 744 and the 737..

The Gateway Bridge area is about 1.5 runway lengths from the airport, so, 5-6 kms roughly. At that distance none of the types have any real flexibility with regard to their height on approach. Basically, if you're on the 3º path, you'll need 300' per nautical mile of distance from the threshold. Whilst you can fix vertical displacement if a bit further out, airlines now all enforce rules with regard to sink rates as you get closer to the ground. At 1,000' you should be 'stable', which means in the slot, and within about 20 knots of the target speed.

Noise levels can also be deceptive. An A380 is inherently quieter than a 747, but if it is decelerating (and so at idle or near to it), then it will make even less noise than a 747 which is on speed. Reverse the situation, and the 747 could appear to be the quieter of the two.

Landing off approaches that have a high start, and which have never become stable, make up a large proportion of all landing accidents.

 

[Major]

The ATSB has released an interesting report into a QF incident where the 738 took off from CBR with 1 degree of flap. I gather this is not a normal configuration

Report: Qantas B738 at Canberra on May 9th 2014, kids are no adults

 

[jb747]

The ATSB has released an interesting report into a QF incident where the 738 took off from CBR with 1 degree of flap. I gather this is not a normal configuration

Report: Qantas B738 at Canberra on May 9th 2014, kids are no adults

The comments at the end of the article are mostly gibberish.

All of the aircraft have multiple possible take off flap settings. Simplistically, use of more flap will give a shorter take off roll, but worse climb out performance. In the case of the A380, the system looks at 3 possible setting for each take off. Back in the days of charts for the calculation, it was too time consuming to look at multiple configurations, and other configs were only looked at if you simply could not take off with a standard setting, but now, with it being done by laptop or iPad, it takes little extra time to look at all of the options.

Generally the trim setting we are given for take off will result in the same stick force being experienced to rotate the aircraft on each take off. If the setting is too nose up, then the aircraft is likely to try to 'self rotate' with an early rotation, with the crew being forced to apply forward stick. This is the opposite, with the aircraft feeling heavy to the pilot. There was never a safety issue with this particular take off, as the trim error was well within the control authority, and it's only the pilot's caution with regard to the unusual configuration and possible tail strike that has made him rotate slowly, and so end up fast. Another pilot might have just pulled harder...and in this case neither would have been wrong.

 

[mrdctau]

Something that I really don't understand from this recent incident in Canberra and previous incidents such as the Emirates tail-strike in Melbourne, is why the aircraft can't calculate its own weight and weight distribution from inexpensive sensors in the landing gear, feed that info into the computer and tell the pilots if something is wrong with the settings they are running with for take-off.

 

[anat0l]

Something that I really don't understand from this recent incident in Canberra and previous incidents such as the Emirates tail-strike in Melbourne, is why the aircraft can't calculate its own weight and weight distribution from inexpensive sensors in the landing gear, feed that info into the computer and tell the pilots if something is wrong with the settings they are running with for take-off.

This might veer off the topic a bit (resulting in a thread split), but what kind of sensors, and how accurate would they be?

Come to think of it, there must be some kind of sensors as such because wouldn't an aircraft need to provide some feedback to pilots in regards to things like fuel distribution / remaining (that needs a sensor) that could affect where the CoG is?

 

[mrdctau]

Hopefully we'll hear from the experts, but a bit of Googling informs me that highly accurate landing gear sensors have been around for many years so I really can't think of any reason why such technology is mandatory to avoid these sort of problems.

 

[jb747]

Hopefully we'll hear from the experts, but a bit of Googling informs me that highly accurate landing gear sensors have been around for many years so I really can't think of any reason why such technology is mandatory to avoid these sort of problems.

Obviously you must be an expert, as you've answered your own question.

Sensors exist. They are not accurate or reliable. Sadly that is the state of the art, but I'm sure Boeing and Airbus have spot for you to help them out.

 

[markis10]

Obviously you must be an expert, as you've answered your own question.

Sensors exist. They are not accurate or reliable. Sadly that is the state of the art, but I'm sure Boeing and Airbus have spot for you to help them out.

Indeed they do exist and some Atlas 744s have them, they use a strain gauge type sensor to measure a bend in the wheel axle, but don't like wind :shock:, filed into the "well it seemed like a good idea at the time" basket.

 

[arbo]

When doing a ferry run overseas for maintenance is it just the PIC & FO and no other crew? Given there are no pax would you still be required to wear full pilot's uniform or could you get away with 'casual Friday' attire?

Thanks JB, Boris and others for keeping such an informative thread going.

 

[mrdctau]

Obviously you must be an expert, as you've answered your own question.

Sensors exist. They are not accurate or reliable. Sadly that is the state of the art, but I'm sure Boeing and Airbus have spot for you to help them out.

lol "expert". I'm an accountant, home handyman, fly a dozen or times per year and did physics at high school a long time ago. Will that get me a job at Boeing?

It seems to me that if quite accurate hand-held baggage weighing machines can be bought on eBay for $10, something similar could be easily designed into the suspension of a plane's landing gear. It may not be balls-on accurate, but it would surely be good enough to detect a 100 tonne data input error like what happened with EK407. Given how seemingly important take-off weight and weight distribution is, I'm really surprised that pilots and airlines aren't pushing for this.

 

[Boris spatsky]

When doing a ferry run overseas for maintenance is it just the PIC & FO and no other crew? Given there are no pax would you still be required to wear full pilot's uniform or could you get away with 'casual Friday' attire?

Thanks JB, Boris and others for keeping such an informative thread going.

Have done some ferries domestically recently but it is just a normal day at work for us, minus passengers and flight attendants.

I do have a friend who flies for a major Asian cargo airline. They wear uniform to and from work, but once onboard it is tracksuits all the way until shutdown!

 

[harvyk]

lol "expert". I'm an accountant, home handyman, fly a dozen or times per year and did physics at high school a long time ago. Will that get me a job at Boeing?

It seems to me that if quite accurate hand-held baggage weighing machines can be bought on eBay for $10, something similar could be easily designed into the suspension of a plane's landing gear. It may not be balls-on accurate, but it would surely be good enough to detect a 100 tonne data input error like what happened with EK407. Given how seemingly important take-off weight and weight distribution is, I'm really surprised that pilots and airlines aren't pushing for this.

That $10 weighing machine might need to support upto 50kg max? a far cry from 350tons of an airliner, not to mention the extreme forces which would go through such a device on landing.

measuring G forces, vs measuring weight requires two completely different methods of measurement.

 

[jb747]

When doing a ferry run overseas for maintenance is it just the PIC & FO and no other crew? Given there are no pax would you still be required to wear full pilot's uniform or could you get away with 'casual Friday' attire?

We will always wear the uniform through the airport terminal. It just helps avoid hassles with the various authorities.

A short ferry (say Melbourne-Sydney) will generally be two pilot. Longer ferries will require additional pilots as per the normal rules. Cabin crew aren't needed for passengers, but on an international ferry, one or two will be carried, just to keep an eye on the back of the aircraft, and to make the occasional coffee. Preflight checks within the cabin can take quite a while, so if you are time constrained at all, someone extra (of any category) might be provided to help with that.

Once in flight, you can wear whatever you like.

 

[jb747]

It seems to me that if quite accurate hand-held baggage weighing machines can be bought on eBay for $10, something similar could be easily designed into the suspension of a plane's landing gear. It may not be balls-on accurate, but it would surely be good enough to detect a 100 tonne data input error like what happened with EK407. Given how seemingly important take-off weight and weight distribution is, I'm really surprised that pilots and airlines aren't pushing for this.

There was substantial discussion about this either in an early part of this thread, or in one directly related to the EK flight.

Gross error checking is something that should be done by the pilots. And the refuellers. And the load sheet people. Basically everyone who works with any numbers. Quite simply...does the answer make sense. Replacing such checks with still more technology is expensive, and whilst it appears to remove the apparent need for the human gross check...'cos the system will do that, invariably it introduces another weak point. The EK (and the very similar Singair) incident might all have been alleviated if the relief crew had actually been part of the preflight. Having everybody, totally separately, source and calculate the data will reduce errors from that source to practically nil. Simple software checks that don't require numerical data entry at all would have caught both (i.e. "does the weight make sense for the route?" as part of the software calculation).

The computers that do the calculations and the FMCs are not normally linked, but some do a rudimentary cross check.

 

[Dmac6345]

Hi jb,
The other morning I had stopped to watch a couple of aircraft land at MEL in some of the thickest fog. They were coming into land on Rwy 16, which has ILS (I think). It was quite amazing. You could hear the engines, but no sight of the aircraft, until I'm guessing 500-800 ft.
It made me think though, a few months ago, I was on QF94 and it was a very foggy morning in Mel. We came in from the S/E over MEB and landed on Rwy 34. What procedures and how is the landing calculated when you cant see a damn thing.
I'm glad it was you (QF Pilots) in the front seat and not me.