Ask The Pilot

[jb747]

So, the only time the left seat is used in flight is by a pilot with a captain's rank? The FO and SO would always use their usual seating, and if there was a second captain for what ever reason, then he would sit in your place when you are on a rest break?

No. The Captain only sits in his seat on the left. The FO only sits in his seat on the right. Any additional pilots, irrespective of their rank, may sit in either seat.

 

[juddles]

JB, yesterday as I got off a LAN Colombia A319 I had to wait on the tarmac next to the left engine (waiting for a shuttle bus). The engine was obviously not running, but with the breeze flowing through it, the main blade arrangement was spinning at changing speeds. There was a very loud metallic clacking which appeared to indicate that each and every turbine blade was striking something metal as it turned.

Is this usual?
Is it harmless? Certainly ground crew didnt seem interested.
Would you get on a plane that made that sound?

 

[jb747]

JB, yesterday as I got off a LAN Colombia A319 I had to wait on the tarmac next to the left engine (waiting for a shuttle bus). The engine was obviously not running, but with the breeze flowing through it, the main blade arrangement was spinning at changing speeds. There was a very loud metallic clacking which appeared to indicate that each and every turbine blade was striking something metal as it turned.

Is this usual?
Is it harmless? Certainly ground crew didnt seem interested.
Would you get on a plane that made that sound?

Totally harmless. I get on jets that make that sound all the time...because they all do.

The blades are not as rigidly attached as you might imagine. They are generally connected to the hub by a system called a fir tree root (type it into google and have a look at the images). As I understand it, this system allows for thermal expansion, as well as doing good job of spreading the loads. It also means that the blades can easily be removed if needed. So, when not spinning, and with no centrifugal force to lock things up, they rattle around.

 

[Tortuga]

Morning JB, came across this question and would love to hear your explanation of the scenario. Thanks

A plane is standing on a runway that can move (some sort of band conveyer). The plane moves in one direction, while the conveyer moves in the opposite direction. This conveyer has a control system that tracks the plane speed and tunes the speed of the conveyer to be exactly the same (but in the opposite direction). Can the plane take off?​

 

[jb747]

Whilst you all seem to have worked out that the conveyor has no effect on the aircraft, but only the wheel rotation...I'd suggest that it probably wouldn't be able to take off, but for a reason you haven't considered.

All aircraft tyres have a rotation speed limit. In the case of the A380, that's 204 knots. So, on your conveyor system, at a normal rotate of about 160 knots, the tyres would be spinning at 320 knots...and would have failed quite some time ago. So, you'd never be able to complete the take off because you would always have tyre failures.

And, having gone to all the trouble of building this Irish conveyor system...why not use it more logically, as a catapult...then you could take off with the park brake on.

 

[mikenz]

Similar question...

If a plane is flying into the wind at the same speed the wind is blowing, does the aircraft effectively hover?

e.g. flying at 500kmh into 500kmh winds.

 

[Boris spatsky]

Similar question...

If a plane is flying into the wind at the same speed the wind is blowing, does the aircraft effectively hover?

e.g. flying at 500kmh into 500kmh winds.

Yep, my personal record is -17 knots groundspeed (which means going backwards). Decent STOL aircraft, strong headwind, full flap and keep her on the stall buffet (at altitude of course). I am sure some of the Caribou guys may have done better than that!

 

[tgh]

but you did it for fun.. plenty of tiger moth pilots who didn't see the fun in it….

 

[QF WP]

Not meaning to sound mean, prudish or moderational; but can we get back to asking questions to jb747 and other pilots...and letting them answer them; after all, that is the reason for the thread:shock:

 

[jb747]

Similar question...

If a plane is flying into the wind at the same speed the wind is blowing, does the aircraft effectively hover?

e.g. flying at 500kmh into 500kmh winds.

Not really similar...yours is a real world question.

The answer to your question is yes. I think I managed it once in a CT4. Back near the stall in approach configuration, in a screaming westerly wind. But at altitude....not near the ground.

Basically an aircraft moves through the air mass at its True Airspeed. If there is any wind, then the entire air mass is also moving. If you happen to be going in the same direction, you can add your TAS and the wind speed together to come up with a ground speed. Going the opposite way, then you subtract the wind speed from the TAS.

Actually if you remember any of your school maths, it's really just a vector sum...

Landing, you want as little energy as possible, so by landing into the wind, your ground speed will be reduced and so will the braking requirements. Taking off, is the same in reverse.

But, if the wind were so strong that you could hover...then it would be a really good time to go to another airfield.

 

[quick_dry]

The blades are not as rigidly attached as you might imagine. They are generally connected to the hub by a system called a fir tree root (type it into google and have a look at the images). As I understand it, this system allows for thermal expansion, as well as doing good job of spreading the loads. It also means that the blades can easily be removed if needed. So, when not spinning, and with no centrifugal force to lock things up, they rattle around.

you touched on it with the centrifugal force - as well as thermal expansion it allows for creep in the blades (where they stretch out due to the forces from spinning quickly). That creep is also a factor in calculating the gap at the end of the blade.

 

[MEL_Traveller]

But, if the wind were so strong that you could hover...then it would be a really good time to go to another airfield.

on a related matter - not sure if this video footage has been posted here before? An empty 747's nose is lifted off the ground by strong winds:

https://www.youtube.com/watch?v=cHhZwvdRR5c

 

[jb747]

on a related matter - not sure if this video footage has been posted here before? An empty 747's nose is lifted off the ground by strong winds:

https://www.youtube.com/watch?v=cHhZwvdRR5c

It would be interesting to know where the 747s CofG was. Move it aft enough, and they'll sit on their tail without any wind at all.

I expect that the CofG was very aft. The lack of engines would have affected that. I don't think the fact that the slats and/or flaps were out made much difference.

The tail normally produces negative lift...i.e. it pushes down. Depending upon just where the trimming tail was positioned, it most likely wouldn't have needed to produce much of that negative force to make the aircraft sit up as it does in the video. Basically, I think it wasn't far from sitting on it's tail anyway, so add a bit of a push on the tail and up it goes.

 

[mjt57]

Basically, I think it wasn't far from sitting on it's tail anyway, so add a bit of a push on the tail and up it goes.

Either that or it's haunted...

 

[ChrisGibbs]

JB747 - I did a couple of flights (NRT-SIN and SIN-SYD) this week on SQ's 380's. Apart from a couple of short SIN-KUL hops I hadn't flown on SQ for a number of year. During both flights the Captain took a walka through the upper deck of the plane. One thing I noticed was that both were wearing a pair of white gloves. I can appreciate military pilots wearing gloves for various reasons however I was under the impression this was an urban myth in the commercial world. Do some commercial Pilots wear gloves? If so is there any particular reason.

Thanks in advance.

 

[jb747]

JB747 - I did a couple of flights (NRT-SIN and SIN-SYD) this week on SQ's 380's. Apart from a couple of short SIN-KUL hops I hadn't flown on SQ for a number of year. During both flights the Captain took a walka through the upper deck of the plane. One thing I noticed was that both were wearing a pair of white gloves. I can appreciate military pilots wearing gloves for various reasons however I was under the impression this was an urban myth in the commercial world. Do some commercial Pilots wear gloves? If so is there any particular reason.

An occasional pilot would, but very rare. Unless you have particularly sweaty palms, I don't see any reason. I think JAL might, as part of their uniform.

 

[andmiz]

I think JAL might, as part of their uniform.

And given extensive ground school courses on how to wear them.

 

[markis10]

A very occasional pilot would, but very rare. Unless you have particularly sweaty palms, I don't see any reason. I think JAL might, as part of their uniform.

I jump seated on a bird seed 744 and the captain wore gloves.

 

[jb747]

I jump seated on a bird seed 744 and the captain wore gloves.

There's a tale within QF about a Captain who wore gloves, and a particularly colourful FO who decided to take the piss by wearing the aircraft fire fighting gloves.

 

[markis10]

I have seen two this month - a green laser on approach to Melbourne got me in the eye and i was off flying for a few days with an inflamed retina. It's just criminal in my opinion. It is beyond me why you would want to point one at an aircraft...

I would add stupid to the labels, especially a 50 year old lighting up polair.

Police have charged an Arundel man with offences committed under the civil aviation act following an incident on the Gold Coast last night.


It will be alleged that around 7.45pm the police helicopter was conducting airborne patrols of the Gold Coast area when the crew noticed a laser light being shone on them from outside a residence in Fadden Close, Arundel.


The helicopter crew reported the alleged incident and police attended the Fadden Close address where a 50-year-old man was spoken to in relation to the matter.


He was issued with a notice to appear in the Southport Magistrates Court at a later date.