Ask The Pilot

[ColinP]

Re: pilots and pregnancy.

From the ICAO Manual of Civil Aviation Medicine

7.5.5 Once pregnancy is confirmed, the pregnant pilot should report to the medical examiner. If declared fit, i.e. if
her pregnancy is considered a normal, uncomplicated and low-risk pregnancy and medical information from her
obstetrician, family physician and/or midwife supports this, she may continue to exercise the privileges of her licence from
the end of the 12th week until the end of the 26th week of the gestational period. Close medical supervision must be
established for the part of the pregnancy where the pilot continues flying, and all abnormalities should be reported to the
medical examiner. Provided the puerperium is uncomplicated and full recovery takes place, she should be able to resume
aviation duties four to six weeks after confinement.

 

[jb747]

Re: pilots and pregnancy.

I've just looked it up in the company paperwork. I was correct, they don't fly at all.

 

[ColinP]

I've just looked it up in the company paperwork. I was correct, they don't fly at all.

If my wife's behaviour while pregnant was typical, then I think not flying at all is a very good idea.
Her driving skills (normally good) and judgement became impaired. She also changed from being a cool, calm person to a hormonally impaired emotional yo-yo.

Interesting that when I looked for info on the CASA site it said this: :shock:

The Designated Aviation Medical Examiner's (DAME) Handbook has been a very useful guide to DAMEs in the past and CASA has received compliments about its quality and its clinical value.

In the past few years, because of limited resources, the handbook has not been updated and is creating misinformation to those who refer to it.

The handbook has been taken down and will be replaced over the next 12-18 months by an updated version.

 

[docjames]

I've just looked it up in the company paperwork. I was correct, they don't fly at all.

Interesting, I wonder how much leave is paid vs unpaid?

 

[jb747]

Interesting, I wonder how much leave is paid vs unpaid?

There are always projects and various ground based jobs that require pilots. I think they do them for a while (if they want, anyway).

 

[Simo]

If my wife's behaviour while pregnant was typical, then I think not flying at all is a very good idea.
Her driving skills (normally good) and judgement became impaired. She also changed from being a cool, calm person to a hormonally impaired emotional yo-yo.

Interesting that when I looked for info on the CASA site it said this: :shock:

Mumzilla....

I don't think it would be real comfortable for a pregnant lady in the coughpit. No pun intended.

 

[Tortuga]

Hey JB, I was reading this article about a Jetblue flight that had hydraulic troubles and this caught my eye

Because the A320 is incapable of dumping excess fuel, the pilots circled the area south of the Vegas Strip until they’d burned enough to allow the crippled plane to land safely.​

Am I correct in thinking that not being able to dump excess fuel when needed is a limitation that shouldn't exist? From the quick research I did it seems that the A320 can land at MTOW if a procedure is followed but this is dependent on the current state/problems with the aircraft?

http://www.foxnews.com/us/2012/06/2...sends-jetblue-flight-careening-through-skies/​

 

[jb747]

Hey JB, I was reading this article about a Jetblue flight that had hydraulic troubles and this caught my eyes "

Because the A320 is incapable of dumping excess fuel, the pilots circled the area south of the Vegas Strip until they’d burned enough to allow the crippled plane to land safely."

Am I correct in thinking that not being able to dump excess fuel when needed is a limitation that shouldn't exist? ​

There isn't very much in the A320 article to really let me know what happened. The loss of two hydraulic systems is extremely unusual, and historically has been the result of something nastier. Passenger comments are so inaccurate as to be pretty much worthless, so it's pretty difficult to read much into what they said. Yaw damper issues could lead to some quite uncomfortable, but not dangerous, motion, which is possibly what they felt.

Looking through various forums on this incident, it seems they actually lost one system, and had an overheat on the other; a dramatically different position to losing two.

I think you'd be surprised at just how few aircraft have fuel dumping systems. In most cases it is not a regulatory requirement, and the vast majority of the narrow bodied aircraft are not so fitted. Even if you have a dump system, it doesn't mean you can dump all of the fuel. Whilst a 747 will let you dump down to about 6 tonnes remaining, on the A380, you'll still have about 80 tonnes of fuel at the end of the dump (and so would be about 30-40 tonnes above max landing weight). The 767s that I've flown had about a 50% fit of a dump system.

The thing you have to remember is that 'max landing weight' IS NOT the maximum landing weight. It is simply the maximum for normal operations, at a defined impact rate (basically an unflared landing at 700 fpm). Believe me, that would be the hardest landing you've ever felt...even VERY HARD landings rarely exceed about 400 fpm. In the A380 you can land at up to max take off weight, as long as the impact rate is less than 360 fpm (most landings are in the 50-100 fpm area). So, the landing itself is not really an issue. In the A380, the vast majority of medical diversions would also include an overweight landing.

The problem comes up when you need to couple a heavy weight landing with other problems. For instance, issues with slats/flaps, brakes, or spoilers, would all lead you to desire the minimum weight possible. But, the regulations that aircraft are built to, don't normally include compounding emergencies (otherwise you could make it so hard that nothing would ever fly). My personal position is that all aircraft should be able to dump all of their fuel. The reality is that that isn't how they are built.

Flying around for a few hours, whilst getting the aircraft to a lighter weight isn't really an issue. If anything, it slows things down in the coughpit, which is probably a good thing. Even if you are in an aircraft that can dump fuel, you're probably still looking at 60-90 minutes for the dump to occur. Even at dump rates it takes a long time to get rid of the very large loads carried by some aircraft. In this particular case, the A320 could have been landed at any time during that 3 hours...

 

[mjt57]

In this particular case, the A320 could have been landed at any time during that 3 hours...

Why do you think that they didn't do this? ie. do you have any theories on it?

 

[jb747]

Why do you think that they didn't do this? ie. do you have any theories on it?

Perhaps because they didn't feel they needed to.

An actual dual hydraulic failure would have given a ECAM 'LAND ASAP' message. I suspect that after actioning the messages, that they would have ended up with an 'LAND ANSA', which is nowhere near as imperative, and which would allow consideration of max landing weight.

Whilst passengers often think that getting an aircraft onto the ground as soon as humanly possible is the best thing to do, pilots mostly think the other way. For instance, on a take off, with an engine failure, the GO decision point is the FIRST point at which continuing becomes available. The last point at which a stop is possible could be some time/distance/speed later. But, it is safer to go flying than it is to carry out a high energy abort. It's the interface between being on the ground and being in the air that can be dangerous. So, delaying that point until everything has been considered, all actions completed, and at as light a weight as possible, is normally a good idea. After QF32, various experts on prune (and other places) were pushing the point that the crew should have landed immediately. As most of us now know, the ONLY reason that the outcome was so good was that the crew took the time to hasten slowly, and did not land until they were ready to do so.

 

[NM]

The thing you have to remember is that 'max landing weight' IS NOT the maximum landing weight. It is simply the maximum for normal operations, at a defined impact rate (basically an unflared landing at 700 fpm). Believe me, that would be the hardest landing you've ever felt...even VERY HARD landings rarely exceed about 400 fpm. In the A380 you can land at up to max take off weight, as long as the impact rate is less than 360 fpm (most landings are in the 50-100 fpm area). So, the landing itself is not really an issue. In the A380, the vast majority of medical diversions would also include an overweight landing.

And a timely reminder that its not just the vertical motion in one direction that plays havoc. This one would not have been very comfortable, and left the fuselage with a few wrinkles! The twisting motion seems to have caused the damage.

Video: Aircraft has a bumpy landing

 

[jb747]

And a timely reminder that its not just the vertical motion in one direction that plays havoc. This one would not have been very comfortable, and left the fuselage with a few wrinkles! The twisting motion seems to have caused the damage.

Video: Aircraft has a bumpy landing

Looks like you have a bit of a stammer there NM.

Watch the video carefully. The 767 touches down on the starboard main. The port main does not touch down. It then gets fully airborne again (which IS NOT a bounce). The nose is then pushed down, and the nose gear impacts whilst the mains are both still airborne. Basically a landing on the nose gear. That's pretty much guaranteed to break anything.

Looks like it's been badly over controlled. Too much nose up at the flare, followed by way too much nose down to stop the subsequent climb. An own goal.

Be interesting to know what the conditions were like. Narita can be a shocker of a place to land. I'm quite glad we don't take the 380s there.

 

[AVC]

OK JB, having said that you could basically land at MTOW (which logically is correct, given a soft enough landing) how does it affect the braking distance? How much runway do you need normally?

 

[Tortuga]

Looks like you have a bit of a stammer there NM.

Watch the video carefully. The 767 touches down on the starboard main. The port main does not touch down. It then gets fully airborne again (which IS NOT a bounce). The nose is then pushed down, and the nose gear impacts whilst the mains are both still airborne. Basically a landing on the nose gear. That's pretty much guaranteed to break anything.

Looks like it's been badly over controlled. Too much nose up at the flare, followed by way too much nose down to stop the subsequent climb. An own goal.

Be interesting to know what the conditions were like. Narita can be a shocker of a place to land. I'm quite glad we don't take the 380s there.

Do you have a rough idea how much force would have been transferred to the fuselage to cause that damage we saw on the video? I'm hoping it was way more significant than anything likely to happen in the sky due to weather etc !! I guess the shock absorbers (do they exist?) can only handle so much.

 

[jb747]

OK JB, having said that you could basically land at MTOW (which logically is correct, given a soft enough landing) how does it affect the braking distance? How much runway do you need normally?

You can land on any runway that you can take off from.....

The most limiting take off runway that we regularly use is 24L in LAX. Going from that runway, at max weight, and TOGA power, leaves you with a margin of 622M.

If you took off, and landed again on the same runway (and miraculously still at that same 569 tonnes), you would have a stopping margin of 877 metres. That does not fulfil the regulatory requirements (as it does not have 66% margin), but, those requirements are tossed out the window in an emergency. But, even those requirements would be met with a fairly minimal (35 tonne) fuel dump....or you could just use the longer runway about a mile south.

Of course the brakes would be warm, and the tyres toast....or you could just make use of that 877 metres and they'd probably all still be good. That huge wing gives relatively slow approach speeds. Much slower than a 747 at a comparable % of max weight.

 

[jb747]

Do you have a rough idea how much force would have been transferred to the fuselage to cause that damage we saw on the video? I'm hoping it was way more significant than anything likely to happen in the sky due to weather etc !! I guess the shock absorbers (do they exist?) can only handle so much.

If I recall correctly, a heavy landing in the 767 was 1.8g. Even then it was unlikely to do any harm, but at that point the engineers had inspections to do. But, that was with no drift, and evenly on the main gear. Side loads would cause damage earlier.

The nose gear was never meant to take the full force of the entire aircraft landing on it, and the bending shown in the video is pretty standard for what was done. Basically, the landing may well have been less than 1.8 g, but the impact was taken at the wrong (single) point.

In flight, you can't really apply force to one spot like that. The loads are distributed more or less evenly across the aircraft. The G limit is 2.5...and I think the testing requirement takes it to almost twice that.

Weather just cannot impose the sorts of loads that will cause the airframe any distress. But, for unrestrained passengers, it really does not take much of a bump for major harm to ensue. A half second push to -.5g would flick you to the ceiling, and then the 1.5 to 2g return to normal flight would have you fall about 7-8 feet with much more than the normal force. Both the positive and negative g figures there are within the normal release of the aircraft so it would be unharmed...though I doubt that the same could be said for anyone not wearing a seat belt. Incredibly cheap insurance, but there's actually a percentage of passengers who keep it undone at almost all times.....

 

[NM]

Looks like you have a bit of a stammer there NM.

Sssstammer fixed now fixed now

Watch the video carefully. The 767 touches down on the starboard main. The port main does not touch down. It then gets fully airborne again (which IS NOT a bounce). The nose is then pushed down, and the nose gear impacts whilst the mains are both still airborne. Basically a landing on the nose gear. That's pretty much guaranteed to break anything.

And something I am sure you don't want to happen in an overweight landing.

Be interesting to know what the conditions were like. Narita can be a shocker of a place to land. I'm quite glad we don't take the 380s there.

So could NRT be the new Tai Kak for exciting landings?

 

[jb747]

And something I am sure you don't want to happen in an overweight landing.

For that reason, an auto land will be done (if possible) in the overweight landing case.

So could NRT be the new Tai Kak for exciting landings?

Narita is prone to some very gusty, strong crosswinds. I remember a viewing area at one of the local hotels where pilots would gather and grade the various arrivals...safe in the knowledge that we didn't have to do it.

Tai Kak was mostly fun. Crosswinds at the runway weren't normally all that strong. The people who used to get themselves into trouble did so during the turn onto finals. If you went through the centreline, then you were in trouble, as there wasn't enough distance to run to fix it. The videos often show aircraft arriving at the runway with their track still not aligned, and dropping the left wing in the flare. That's a set up for a pod scrape in the 747.

Here's a link that showed what it looked like http://www.oobject.com/videos-of-pl...video-landing-hong-kong-kai-tak-airport/7722/

and the sort of picture you don't want to feature in http://www.iasa-intl.com/folders/belfast/101103/image17.html

 

[jetlagger]

Thanks so much for the interesting insights & clear explanations jb747.. Really appreciated!

 

[Mattg]

We were told that we would have a short delay arriving into SYD this evening due to "ATC Sequencing Requirements". Any idea what that might be?