Ask The Pilot

[jb747]

I recall from air crash investigations that a few accidents happened due to the total loss of hydraulic fluid, is it something that can still happen on a modern plane such as A380 and B787 or are there backup system in place that will allow some control even with the total loss of hydraulic fluid?

The A380 only has two hydraulic systems, and they run at 5,000 psi. Total loss of both hydraulic systems takes away things like normal landing gear operation, but the flight controls remain fully powered. The controls (and brakes) are powered by a mix of direct hydraulics (which will be gone after a loss) and local electro hydraulic packages, which will work as long as there is electricity.

I'd expect the A350 to be the same. I don't know about the late model Boeings, but expect that the 787 would have similar.

Large aircraft normally have 3 or 4 hydraulic systems, which are as isolated as the engineers can manage. Flaps and slats may be a mix of hydraulics, pneumatics, or electrical operation. Gear will be hydraulics and gravity. Flight controls will distribute mixed hydraulic circuits around the various surfaces, so that you may lose some, but not all with most failures.

 

[jb747]

How heavy must turbulence be before engineers are called in to check the plane? Is there some sort of sensor that if tripped during turbulence the plane needs to be inspected?

I guess that if the pilots' underpants needed replacement, then that would work as your sensor. Beyond that, g loadings can be recorded around the aircraft, though I've never heard of them causing an inspection, other than after a heavy landing. I've never heard of a turbulence inspection, so for it to be called for, someone must have found some particularly nasty weather.

Just wondering as that's the reason I was given in the lounge as to why I've just been bumped to an earlier flight this afternoon.

I don't think people at the gates/lounges are given particularly detailed explanations of any changes. And I expect they're also a number of levels down the chain, so there's plenty of room for a 'tyre change' to become a 'landing gear replacement'.

 

[glasszon]

I guess that if the pilots' underpants needed replacement

I laughed at that part, what would be the most scary thing a pilot can experience during a routine flight? I assume they are not worried about turbulence

Edit: Thanks so much for sharing your insights, it's great to hear from a pilot (A380 captain no less) talking about aviation. It really is an eye opener.

One more question and this one is a bit more personal, are you familiar with the revenue management team and how do people enter that area? Speaking as someone who have a quantitative background and would love an opportunity to apply that in a major Airline.

 

[jb747]

I laughed at that part, what would be the most scary thing a pilot can experience during a routine flight?

Running out of ideas.

I assume they are not worried about turbulence.

Not really. The sort of turbulence that most people complain about may make it impossible to walk around the cabin, but as far as the aircraft is concerned, that’s not even a rough road.

One more question and this one is a bit more personal, are you familiar with the revenue management team and how do people enter that area? Speaking as someone who have a quantitative background and would love an opportunity to apply that in a major Airline.

You might be surprised at just how little pilots have to do with the various towers of power [to use a nice phrase] around the place. In these days of iPads, there is no meeting before flights in a briefing room. We go straight to the aircraft, discuss the flight plan, and go. Afterwards we immediately leave the airport. If you aren’t a pilot, or cabin crew, or an engineer, then you will have zero dealings with the pilots. A recent story had an office lass asking a uniformed Captain what he did in the company. The disconnect between operations and everything else, is a chasm. So to answer your question, whilst such a group probably exists, I would have no idea what planet they are kept on.

 

[harvyk]

I guess that if the pilots' underpants needed replacement, then that would work as your sensor. Beyond that, g loadings can be recorded around the aircraft, though I've never heard of them causing an inspection, other than after a heavy landing. I've never heard of a turbulence inspection, so for it to be called for, someone must have found some particularly nasty weather.



I don't think people at the gates/lounges are given particularly detailed explanations of any changes. And I expect they're also a number of levels down the chain, so there's plenty of room for a 'tyre change' to become a 'landing gear replacement'.

Whilst I know it's impossible for me to know from row 8, I suspect you're right that it was simply a hard landing on the preceding flight. It was very turbulent on take off, but I've experienced much worse turbulence than that. That said the turbulence was very close to the ground so I could easily imagine it being a hard landing on the previous flight.

On boarding the pilot apologized for the delay but it was due to them needing to switch aircraft since the original one was declared unserviceable. I did note that there was a couple of pilots on our flight deadheading back to SYD.

 

[jb747]

Interestingly, in my experience, pilots report hard landings well before they actually are. Overseas, not so much. I've reported two. Both were very solid, but well under the limits...but it's always best to be the one ringing the boss, and not the other way around.

One was an actual wind shear encounter, very close to the ground. The other was when I first started flying with glasses, and I just misjudged it. In the shear case, we lost 27 knots, in 1.5 seconds, and arrived at full power. Thankfully I held the attitude, otherwise we'd have had a nasty tail impact. So very solid, but no harm done.

 

[Quickstatus]

Flying with vision correction:

Apart from the optometrist prescription are there any necessary adjustments/calibration for aviators when vision correction is necessary?

 

[AviatorInsight]

Flying with vision correction:

Apart from the optometrist prescription are there any necessary adjustments/calibration for aviators when vision correction is necessary?

I'm assuming you're talking about the minimum corrections? 6/9 in each eye to be corrected if necessary (separately) and additionally 6/6 or better with both eyes open.

 

[Quickstatus]

I'm assuming you're talking about the minimum corrections? 6/9 in each eye to be corrected if necessary (separately) and additionally 6/6 or better with both eyes open.

No,

Once vision has been corrected by the optometry prescription, are they any calibrations that are necessary by the system or individual ? - is what you are seeing out the window with vision correction what you are supposed to be seeing?.

I require reading glasses. So near sight needs correction. My reading glasses make what I am seeing (reading) a little larger than what they really are.
If far sight is corrected (for looking out the window) what is seen may be different in size to what it is in reality and may influence the pilot’s aviating actions and timing of their actions.

 

[eric2011]

If far sight is corrected (for looking out the window) what is seen may be different in size to what it is in reality and may influence the pilot’s aviating actions and timing of their actions.

I take it you are talking about this post from jb747 or similar

The other was when I first started flying with glasses, and I just misjudged it.

 

[MickC32]

Following on from the glasses theme, is there a minimum unaided vision requirement for commercial pilots? Or is it all good as long as you have the specs on?

Also, does anyone else sing "Ask The Pilot" to the tune of "Drop the pilot, try my balloon" in their head when they open this thread or is it just me?

 

[AviatorInsight]

No,

Once vision has been corrected by the optometry prescription, are they any calibrations that are necessary by the system or individual ? - is what you are seeing out the window with vision correction what you are supposed to be seeing?.

I require reading glasses. So near sight needs correction. My reading glasses make what I am seeing (reading) a little larger than what they really are.
If far sight is corrected (for looking out the window) what is seen may be different in size to what it is in reality and may influence the pilot’s aviating actions and timing of their actions.

I actually wear contact lenses for distance. So I go to my optometrist and say I need it corrected. We go through the motions and he gets me a suitable power to correct my vision to 6/6. I don’t require any calibrations and as such don’t believe it influences my actions and or timing. Maybe you’ve experienced some of my landings and this is what prompted the question?

 

[AviatorInsight]

Following on from the glasses theme, is there a minimum unaided vision requirement for commercial pilots? Or is it all good as long as you have the specs on?

Also, does anyone else sing "Ask The Pilot" to the tune of "Drop the pilot, try my balloon" in their head when they open this thread or is it just me?

For commercial pilots like I stated above 6/9 in each eye (corrected or not), but both eyes need to be 6/6 or better.

 

[Quickstatus]

I actually wear contact lenses for distance. So I go to my optometrist and say I need it corrected. We go through the motions and he gets me a suitable power to correct my vision to 6/6. I don’t require any calibrations and as such don’t believe it influences my actions and or timing. Maybe you’ve experienced some of my landings and this is what prompted the question?

Ha no i was only exploring @jb747 comment about his first? Landing after using glasses.

I’ve actually never experienced a bad landing - in so far as the aircraft always gets to the gate after landing under its own power. As far as I’m aware those aircraft also manage to take off later as well. That’s enough for me.

 

[747sp]

In the theme of bad landing I was wondering with the old Hong Kong airport with the sharp right turn before you land there are number of photos and videos of planes landing not straight.
ie the wheels are not in the same direction as the nose.
Are the landing as dangerous as they look and what did the pilot do wrong?
Where the take offs in Hong Kong towards the checkerboard as difficult as the landings?

 

[RooFlyer]

In this AH report of a multi-engine failure on an SQ flight in 2015, one of the reasons was found to be (my bold):

Engine No.1 was disassembled and the examination of the engine suggest that the engine surge in Engine No. 1 was most likely a result of the release of IPC rotor path abradable lining material. Although Engine No. 2 was not disassembled and examined, it is most likely that Engine No. 2, being as new as Engine No. 1, experienced the engine surge for a similar reason.

What, in layman's terms, is IPC rotor path abradable lining material and what does it do, please? (Sure, I've Googled it, but mostly just refers to the SQ incident) Ever heard of it coming 'off' previously and causing engine issues?

What I can't understand from the AH report is why both engines should surge and then stall at exactly the same time, if the offending material is somehow within each engine. Also that the crew, after multiple stalling and self-restart of both engines, decided to continue to destination rather than diverting. Also a bit surprised that the aircraft carried on 4 hours later, apparently without an internal inspection of engine #2.

Any comments from our pilots?

 

[jb747]

One of my passengers was also an ex A4G pilot. He came up and reminded me that I no longer needed to aim for 3 wire.

Definitions of a bad landing vary. Thumping it in, isn't necessarily bad at all. The greasers that cabin crew and passengers so like, generally waste runway, on a wet runway expose you to aquaplaning, and in a crosswind make it much more likely that you'll drift off centreline.

 

[jb747]

I have no idea what the actual vision standards are. I'm borderline for needing glasses for distance, but most definitely need them for reading. The problem is that coughpits have things that you need to read at about a metre distance from you, as well as have overhead panels that are very close. So, I have a set of look overs that are aimed that that 1-1.5 metre range, and I make sure that the upper edge of the glasses aligns with the instrument coaming. For the overhead I need to put them on properly.

I've tried a couple of different styles of bifocals. Normal ones don't work at all, but I recently had a set made up in which the top third has a distance correction, and the lower two thirds are my intermediate. Again the junction aligns along the coaming. They work well.

Varifocals do not work at all. They require you to move your head to see things, instead of just a flick of the eyeballs, and that's quite vertigo inducing.

 

[jb747]

In the theme of bad landing I was wondering with the old Hong Kong airport with the sharp right turn before you land there are number of photos and videos of planes landing not straight, ie the wheels are not in the same direction as the nose.
Are the landing as dangerous as they look and what did the pilot do wrong?

There are some wonderful pictures of landings at Kai Tak. It was actually quite a straightforward exercise, as long as you'd had a think about it beforehand. The issue was always crosswind, and making sure you allowed for it correctly in the turn. If you did the turn correctly, you lined up at about 250'....which is fine, but if you got it wrong, then that does not allow sufficient time to fix things. Basically, if you weren't in the right spot, tracking the right way at 250', then it was already time to give it away.

The issue I saw most was a crosswind from the right on the runway. That meant a bit of tailwind on the initial part of the approach and through the turn the wind would be pushing you wide.

That video was actually shot by a 767 Captain, and has become very widely viewed. It's an absolutely appalling landing. He very nearly has a pod scrape, he is short of the threshold, and his energy is not aligned with the runway. I actually saw a BA aircraft hit the outboard engine on a landing there, but at least he was over the keys.

Where the take offs in Hong Kong towards the checkerboard as difficult as the landings?

Not that I recall...take off and turn left.

 

[mjt57]

Definitions of a bad landing vary. Thumping it in, isn't necessarily bad at all. The greasers that cabin crew and passengers so like, generally waste runway, on a wet runway expose you to aquaplaning

We landed in Honolulu in the middle of a storm. The B787 landed with quite a thump. People around me complained, especially my wife.

As I was uncompacting my vertebrae I explained why we probably thumped down (not touched down) was likely due to the reasons you've explained above.