V-Flyer

It seems that quite a few people are un-nerved by all the odd sounds and weird feelings that you experience on a flight. So I thought it maybe useful and interesting if we put together a list of them all, and their proper explanation. That way, when people hear 3 bings, they will know it is not the Captain telling the crew the plane is about to crash!

The Push Back
- When you get onto the plane it maybe plugged into the airport's power supply. However it may also be using its own generator (Auxiliary Power Unit, APU) in the tail. This will be that high-pitched scream you hear.
- When you sit down, you may notice smoke coming from the air conditioning vents above the windows. The plane is not on fire! It is simply the cold air condensing water out of the warmer moist air that is already in the plane. You will also hear a load of clunks and bangs. This will be the crew wheeling and stowing the food, and more importantly the duty free. It will also be the ground crew throwing your luggage into the hold (as hard as they can!). You may also hear them closing the cargo doors, making a whir and a thump.
- The crew will then close and arm the doors. Arming involves turning on the shoots that will go off automatically should the doors subsequently be opened. They then double check this, and ensure that the safety pins (usually with a big red ribbon attached to them) are inserted into the arming mechanism. "Cross check complete" is then reported to the flight deck.
- As the engines start the aircon will stop and the lights dim. This is not an electrical fault, but just the result of the power being switched from the APU (mentioned earlier) to the main engine generators.

Taxi
- As you taxi to the runway you may smell and acrid burning odour. This would be the exhaust from the plane in front of you - not nice, but nothing to worry about.
- The bump, bump you hear is the wheels going over the expansion joints in the concrete taxiway.
- The brakes may squeal as you slow. Again this is just dust and debris on the friction surface of the brakes and nothing to be concerned about. On an Airbus you may also hear someone having a go at the plane with a large electric drill. In fact this is the Power Transfer Unit, which takes power from one engine to another - an Airbus feature.
- While on the ride to the runway the flaps and slats (the bits that move at the back and fronts of the wings) to test them. They will then extend them into the position they should be for take off, with a whirring of gears and wheels.
- There will be a few bongs on the intercom system just before take off. This tells the crew to sit down, and may be accompanied by an announcement like "cabin crew be seated for take off".
- Everything in the galleys should be properly secured. However you may hear a few things falling over as the plane starts its acceleration down the runway. You may also see the lockers above your head shaking and wobbling around - they are designed to do this.
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The first moments of flight
- Many airports require a turn pretty quickly after take off. This can be for air traffic control reasons, or to avoid flying noisily over too many houses. It can be disconcerting to see the sky out of one window and the ground out the other. While the turn is perfectly normal (and it is unlikely the plane is banking more than 20 to 25 degrees), if this worries you don't look!
- You will then hear the clunks and bangs of the wheels being retracted - this is done by one of the crew who stays in the hold during take off with a big spanner to wind them up . The wheels may have been spinning at 100mph or more at take off, so you might feel some vibration as the brakes stop them spinning.
- I think the worst feeling is the swooping, plunging feeling you get about a minute after takeoff. In fact you are just slowing down a little and the upward pitch of the plane reduces slightly - the plane is still accelerating and climbing. But it feels for all the world like you have suddenly gone into a dive - our bodies are remarkably sensitive to changes in acceleration and pitch when deprived of visual reference points. This again is a noise abatement measure, and is very popular with the folks down below in their sitting rooms.
- You may also feel a little turbulence which is caused by thermal effects on the air above the hot city/hills/desert you are flying over, the clouds you are passing through, or the change in temperature as you move from over land to over sea.
- at 10,000 feet the pilots will use the intercom to bong again - 10,000 feet is a key point in the rules relating to air-travel.
- Finally you hear the flaps and slats adjusting to their in-flight positions. And it's time for a drink [y]

The approach
- The crew will throttle back the engines to start the aircraft descending. As the aircraft slows they will start to extend those flaps and slats again. Passing 10,000 feet there will be the bong again.
- At some point large flaps on top of the wing called spoilers will be extended. These slow the plane still further, but they also cause a very choppy flight for a while.
- As you actually come into land one of three things will happen. The engines will probably rise a bit in pitch, and the plane may wobble around a bit. This is the pilot making last minute fine adjustment to the rate of decent. This will make the landing smoother - what a considerate fellow! Alternatively there maybe no change, which means the pilot is so good that she got it all bang on from the start (or she is a little less considerate). Very, very occasionally the engines will go to high power and you climb off again. This is a normal manoeuvre and can be for many reasons - an unexpected gust of wind, a deer on the runway, even "something doesn’t quite feel right". Usually it’s the plane just before you not exiting off the runway quite quickly enough. Very rarely you may briefly touch down before rising again for the "go-around". Either way, this is not a last-ditch manoeuvre, and is well planned for by the crew and air traffic control.
- The wheels will touch the ground - back ones fist then the front ones - and the engines will fire up in reverse thrust to slow the plane. The spoilers will also shoot up (and sometimes other bits on the engines, which is to do with the reverse thrust) and the brakes will squeal.
- If the pilot lands right in the middle of the runway you will hear the wheels bumping as they roll over the centreline lights, a bit like cats eyes on the road. As the plane taxis you will hear the flaps and slats retracting again, and the Power Transfer if you are on an airbus.
- The seat belt sign will finally go off, with another bong of course, and the power may be switched to the APU with another flashing of lights. Welcome to London Heathrow, it's time to complain about your lost luggage!

There is one noise I have never worked out. If is during climb, but only sometimes, and sounds like ball bearings rolling down inside the roof above your head - any ideas anyone?

Jeremy

Thanks for the detailed and informative post.

I think the ball bearings to which you refer are the marbles that the locker pixies use in their games to while away the time between bouts of rearranging your luggage in the overhead bins.

Two follow ups:

1. Is it possible for luggage to move around in the hold ? I swear I've heard random thumps and clunks in flight..

2. Is the angle of flight with the nose slightly up or is the interior sloped ?

Paul

What an excllent topic. I'll be passing this onto my other half who is a nervous flyer. She's actually going on the VS flying without fear course in a couple of weeks, so I can add any comments she brings back then.

A couple of points to add, although I think you've covered most of them:

(1) I think its worth noting that a lot of the noises do vary from aircraft to aircraft. I went for a considerable stretch flying only on A320/321, and 777, all of which were very quiet and then went on a circa 1990 767 last year, and noticed that all the noises (flaps, undercarriage, brakes) were all a lot louder and more 'mechanical' sounding than the 'electrical' noises you get on the newer aircraft.

(2) The engine noise varies considerably depending on where you are sat in the cabin. It's much quieter (and a different sound altogether) if you are sat in front of the wing.

(3) On approach, you may feel the aircraft speed up, and the engine noises getting louder. This is usually for two reasons. Firstly, it is adjustments to the rate of descent as explained above. Secondly, when the flaps are extended, this makes the aircraft much less aerodynamic, and much more power is required to keep the aircraft going at the required speed.

(4) Finally, re the angle of flight question above, it basically depends on how heavy the aircraft is. Early on in the flight, when the aircraft is full of fuel and therefore very heavy, a slight upward angle will be needed to maintain level flight. As this is burned, the aircraft will tend to level out more. However the angle is very small. It tends to look bigger to me when I look forward up the cabin, but when I look out the window, it is very small or non-existent.

Mark

Originally posted by mavml
She's actually going on the VS flying without fear course in a couple of weeks, so I can add any comments she brings back then.

Would it be possible to get a review of the course for this site. I may be wrong, but I don't think we have one, and suspect a number of people would be interested what it is like (particularly as you can buy it with miles I think).

No problem - just let me know where to post it!

I think its the first weekend in July at LGW, so i'll get something together a few days later for this site. I'll be pleased to contribute, as I've learned so much about VS from the site having not yet flown with them, it will be nice to give something back (and yes I do plan to buy a membership kit, just haven't got round to it yet!).

Originally posted by mavml
I'll be pleased to contribute, as I've learned so much about VS from the site having not yet flown with them, it will be nice to give something back (and yes I do plan to buy a membership kit, just haven't got round to it yet!).

While the money does help, by far the most important thing is the two way contribution everyone makes to help each other. Thank you for your past and future contributions - its great that people like you take the time to share.

Your report on the flying without fear course would be great. I would post it in this, the general discussion forum, as a separate thread.

Good information for nervous flyer nice one Sailor. [y]

Is it possible for luggage to move around in the hold ? I swear I've heard random thumps and clunks in flight...

I sincerely hope not! Perhaps the sounds your refer to are MHC [:0]

Um, MHC? What's that?

Great topic.. I too have wondered what the " Bong @ 10,000 feet indicates".

I once moved the wrong lever on the jumpseat while on a trip to the US and this caused the seat to go very rapidly to it's lowest height position ably assisted by my 18 stones on top of it.

Being on a 747 directly above row 8/9 the bang as I hit the floor caused a call to the F/D asking "What was THAT??" [:I][:I][:I]

Yours plumply,

John

What a great thread Sailor!

Somewhat elitist, but shortly after the return for service for Concorde - I took my younger sibling Christmas Shopping in NYC on Concorde as his 21st Birthdya present - now I've flown a fair bit, and I am so glad they did the passenger briefing on what would happen and sounds you would hear! After take off the plane veered a sharp left, and the noise instantly halved as they switched off the fuel injection at which point the whole plane went quiet, even though we had been told what was happenning! It sounded like the engines had been switched off [:0]

Would love to hear the review of the Flyign Without Fear course, as I know a couple of people that would be suitable candidates!

Thanks,
Richard

Originally posted by sailor99
On an Airbus you may also hear someone having a go at the plane with a large electric drill. In fact this is the Power Transfer Unit, which takes power from one engine to another - an Airbus feature.

Excellent stuff here [y]

You forgot to say that on the Airbus A346 you can quite often hear the Captain shouting 'fly godammit fly' as it seems to take an eternity to get off the ground

Originally posted by sailor99
Um, MHC? What's that?

mile high club

Oh, I see. Doh![:I]

I understand VS redesigned the nappy changing table in their toilets a while back because they kept getting broken. There must be some darn heavy babies out there, unless something else were the cause[}:)][:X]

After take off the plane veered a sharp left, and the noise instantly halved as they switched off the fuel injection at which point the whole plane went quiet, even though we had been told what was happenning! It sounded like the engines had been switched off

The Canarsie Climb quite an experience[oo]

Originally posted by sailor99
Oh, I see. Doh![:I]

I understand VS redesigned the nappy changing table in their toilets a while back because they kept getting broken. There must be some darn heavy babies out there, unless something else were the cause[}:)][:X]

VS redesigned their toilets after a complaint...

I've always thought that Airbusses make a lot more noise when they're taxing than Boeings.

Does anyone know exactly why they bong at 10,000ft?

The "bongs" are usually signals to the cabin crew during taxiing out to the run way you will often hear 2 bongs - this is to inform the crew that we are about to take off - sometimes the flight deck will say "cabin crew - seats for take off " - after take off it means that flight deck is letting them get up and move around the cabin to prepare for the food and beverage service.

During landing its normally used once again to inform the cabin crew that they now need to sit down ready for landing - again sometimes the flight deck will make an announcement.

The other time you may hear "bongs" is when someone is either calling for a crew member, pressing the crew call button by mistake( sometimes lights and crew call button are close together - especially on handsets) or someone is just messing with the crew call button!!

Let me throw caution to the wind and set myself up for some serious correction by one of our flying gurus or staffers[xx(][B)]

The bongs at 10000 feet mean a bit more than just that the crew may move around. With in 10,000 feet of landing or take off the flight crew are so busy that under most air regulations they are required to keep a sterile cockpit - by which it is meant that no one may interrupt, and nothing can be discussed apart from the operation and safety of the flight. The bong on climb also indicates that this period is over, and that the crew can interrupt the flight deck if they need to.
Some airlines also bong at 18,000 feet. I believe this is the level at which aircraft, or US ones at least, are subject to Federal Air Traffic Control. It is also the level at which heights are discussed in terms of Flight Levels (eg FL270 is 27,000 feet). Westbound aircraft fly on even flight levels (eg FL240) and east bound on odd ones. Above FL290 a 2000 foot gap is maintained so the eastbound flight levels become 290, 330, 370 and so on while west is 310, 350, 370 etc. So FL180 is symbolic of the flight reaching cruising heights - and this event is marked by another bong on some airlines. It also means you should be able to tell if you are heading west, and therefore can look forward to wonderful Florida sunshine, by looking at the height on v-port. If you find yourself flying at 33000 or 37000 feet, I am afraid all you can look forward to is British fog and rain! Just to make life difficult some countries use metric flight levels (China for example). [|:)]

So do I get a pink anorak or a flame suit!

Blimey thanks Jeremy - you never stop learning do you!!

Oh and sorry - definitely the flame suit IMHO[^]

18k ft is only applicable in the US Jeremy, as you say.

Here in the UK, your "transition altitude" (the height at which you set your altimiter to "standard" - 29.92" / 1013.5mb) is issued by ATC.


More (somewhat basic) info here.

Originally posted by RichardMannion
[brand the noise instantly halved as they switched off the fuel injection at which point the whole plane went quiet, even though we had been told what was happenning! It sounded like the engines had been switched off [:0]

Well if they did turn the "Fuel Injection" off the engine's would stop, i take it you ment the after burner's[:w]

Sort of related to this topic - one thing I did notice on all my recent A346 VS flight's and being sat down the back - it amazed me how much the middle over-head console that streches the W and Y cabin moves and flexes a good few inches during take-off.

I know it's 100% perfectly normal for these parts to move and flex as if the cabin fixtures were fixed solid and not able to move around, the cabin would shake itself apart.

Regards

On all of the LGW 744s I've flown on (VS) I have noticed several common noises that I don't notice on other airlines (but then I don't often fly 744s from other airline).

1) There is a rubbing noise from the nose wheel when cornering on the ground.
2) There is a loudish whir as the wheels are retracted after take-off followed by a satisfying fizz and a final bump after which everything generally smooths out
3) If you sit if 6A or K you can here something in the nose cone move back and forth, which I believe was identified in a previous thred as radar or something similar.

The one thing I notice with Airbus generally is that when the power is put on for take off you hear a constant same pitch whistle that lasts pretty much until crusing altitude is attained.

Does anyone know why the LGW 744s nose wheels are so noisy when cornering?

Paul