Avro RJ100 take off / landing question
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Avro RJ100 take off / landing question
First off, just want to say... first post here, have searched the forums and couldn't find the answer so but if this has been done, sorry
OK, my question involves the above aeroplane, I’ve been on a few flights recently and noticed something which i thought was unusual, have thought of plenty of reasons why it might be done, but now looking for ”the truth"
On the ramp, you can hear distinct start up noises on only 2 engines. Pilot then applies first notch of flaps (at most fields, on short fields like LCY it's full flaps)
Plane takes off and then at what seems like about 2-3000ft whilst the final stage of flaps are withdrawn there is a distinct change to the engine noise which sounds like a start up.
same procedure in reverse on landing, as the pilot deploys first stage of flaps, there is again a change in engine note which sounds like engines being shut down.
(Sorry for the big war and peace effort, nearly there)
I can thing of a view reasons why this might be done. Unpredictable yaw control from loss of one of the outside engines on take off, noise abatement and possibly some form of structural / aerodynamic limit.
So a few questions then..... (Still here then!)
1) Am I right? are engines being started and stopped in flight?
2) if so why?
3) Which engines 1 and 4 or 2 and 3
4) any other aircraft have similar restrictions (I know the venerable dash 7's pilots only apply 50% to 1 and 4 for part of the take off from Courcheval in France, but that's because of a significant change in RW attitude can make the front wheel go light over the transition. apparently a loss of power at that point could cause a catastrophic directional control problems… search for the dangerous airport database on t’internet for more)
Phew, thanks for putting up with my long winded rambling
OK, my question involves the above aeroplane, I’ve been on a few flights recently and noticed something which i thought was unusual, have thought of plenty of reasons why it might be done, but now looking for ”the truth"
On the ramp, you can hear distinct start up noises on only 2 engines. Pilot then applies first notch of flaps (at most fields, on short fields like LCY it's full flaps)
Plane takes off and then at what seems like about 2-3000ft whilst the final stage of flaps are withdrawn there is a distinct change to the engine noise which sounds like a start up.
same procedure in reverse on landing, as the pilot deploys first stage of flaps, there is again a change in engine note which sounds like engines being shut down.
(Sorry for the big war and peace effort, nearly there)
I can thing of a view reasons why this might be done. Unpredictable yaw control from loss of one of the outside engines on take off, noise abatement and possibly some form of structural / aerodynamic limit.
So a few questions then..... (Still here then!)
1) Am I right? are engines being started and stopped in flight?
2) if so why?
3) Which engines 1 and 4 or 2 and 3
4) any other aircraft have similar restrictions (I know the venerable dash 7's pilots only apply 50% to 1 and 4 for part of the take off from Courcheval in France, but that's because of a significant change in RW attitude can make the front wheel go light over the transition. apparently a loss of power at that point could cause a catastrophic directional control problems… search for the dangerous airport database on t’internet for more)
Phew, thanks for putting up with my long winded rambling
Rallymania,
You normally won't hear No 1 being started as it is masked quite nicely by 2, 3 and 4 which are already running (if the starting seq is 4-3-2-1). All donks are started priot to takeoff, BTW.
The "windup" sound you hear airborne is the "airflow induced noise generated by the retraction of the wing flaps", as our FAs say on the PA. The reverse happens as the crew extend the flaps for landing.
It's THE trademark of the BAe 146/RJ. In addition to the fumes!
You normally won't hear No 1 being started as it is masked quite nicely by 2, 3 and 4 which are already running (if the starting seq is 4-3-2-1). All donks are started priot to takeoff, BTW.
The "windup" sound you hear airborne is the "airflow induced noise generated by the retraction of the wing flaps", as our FAs say on the PA. The reverse happens as the crew extend the flaps for landing.
It's THE trademark of the BAe 146/RJ. In addition to the fumes!
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Doh!
so completely wrong then lol! thanks capn bloggs for putting me straight
(BTW you meantion your FA's announce this to your passengers, which airline? i've self loaded in this type several times with BA and it's never been meantioned on the PA)
out of curiosity how does retracting / extending the last / first stage of flaps generate so much noise when the rest of the flap re-configuration doesn't? i would expect a change in the amount of lift beng generated by the reconfigured wing and obviously a change in drag as a result but what is it about the configuation of the RJ that causes this noise?
i know, if i was a cat i'd have died about 20 years ago :-)
(BTW you meantion your FA's announce this to your passengers, which airline? i've self loaded in this type several times with BA and it's never been meantioned on the PA)
out of curiosity how does retracting / extending the last / first stage of flaps generate so much noise when the rest of the flap re-configuration doesn't? i would expect a change in the amount of lift beng generated by the reconfigured wing and obviously a change in drag as a result but what is it about the configuation of the RJ that causes this noise?
i know, if i was a cat i'd have died about 20 years ago :-)
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Flap
The thing is that first selection of flaps is 18. Quite unusual for a jet transport aeroplane. At the speed of arround 200 kt where you can start a flap extension, its is quite drag change. After that 24,30,33 are selected at lower speed and difference between 30 and 33 isn't much. As far as engines are concerned, the quite unique thing that from starter engage to starter disingagement takes about 17-18 seconds. So in day to day ops it takes less time to start 4-3-2-1 on RJ than 2-1 on B733. The reason is electric starter, of course. The ALF engine itself comes from Chinook helicopter. All in all odd machine, but flies nice and landing is a peace of cake, allways smood and pax friendly
your FA's announce this to your passengers, which airline
Why the noise? Who knows! I believe BAe spent some time trying to work out what caused it (with a view to fixing it) but couldn't!
There was a considerable thread here a while ago about the 146 flap extension noise, it seems the noise is an aerodynamic one between the flap inner edge and the wing/fuselage at certain angles of deployment. It seemingly came as a surprise to BAe on the first test flights ! They developed a mod but it weighed 100 kg = loss of two revenue pax so not applied.
Out of London City rwy 28 the flaps are usually taken in after the 180 degree turn when passing overhead Stratford at 3,000 feet. The retraction noise is quite audible from the station platforms and presumably will be from the Olympic Stadium alongside as well; listen out for it from anywhere in the world when watching the 2012 Olympics and see if the commentators notice it !
I've done many sectors as pax on the 146 over the years. In addition to the flap noise (which I have NEVER heard crews caution about) and the fumes, a feature of them when on the ground in humid conditions used to be very noticeable "steaming" from the upper air-con ducts the length of the cabin. That did used to require a placating PA, but I haven't noticed it in recent years. Has there been a mod ?
Aer Lingus skippers used to warn about the full power engine runup against the brakes when ready for departure from London City, which was amusing - and made you realise they are NOT hairdryers ! Must have startled someone.
Out of London City rwy 28 the flaps are usually taken in after the 180 degree turn when passing overhead Stratford at 3,000 feet. The retraction noise is quite audible from the station platforms and presumably will be from the Olympic Stadium alongside as well; listen out for it from anywhere in the world when watching the 2012 Olympics and see if the commentators notice it !
I've done many sectors as pax on the 146 over the years. In addition to the flap noise (which I have NEVER heard crews caution about) and the fumes, a feature of them when on the ground in humid conditions used to be very noticeable "steaming" from the upper air-con ducts the length of the cabin. That did used to require a placating PA, but I haven't noticed it in recent years. Has there been a mod ?
Aer Lingus skippers used to warn about the full power engine runup against the brakes when ready for departure from London City, which was amusing - and made you realise they are NOT hairdryers ! Must have startled someone.
Bottums Up
Noisy flap extension does have some benefits.
If one lives close to the airport, one can execute a Hi honey, I'm home by judicious selection of Flap 18 as one approached overhead honey's home.
S/he will have no doubt that one is soon to walk throught the front door.
WBHM
I'll second Bloggs (lover of smurfjets as he is
). Every NJS 146 safety demo contained advice that went something like, "shortly after takeoff and before landing you will hear an airflow induced noise associated with the retraction and extension of the wing flaps. This noise is normal."
Numerous PA about the condensation cloud from the a/c ducts, particularly in the tropics with humidity of 96% in the morning.
rallymania
Was it really full flaps? When Bloggs taught me all I know we only had takeoff performance data for Flaps 18, 24 & 30. None for Flaps 33.
If one lives close to the airport, one can execute a Hi honey, I'm home by judicious selection of Flap 18 as one approached overhead honey's home.
S/he will have no doubt that one is soon to walk throught the front door.
WBHM
I'll second Bloggs (lover of smurfjets as he is
). Every NJS 146 safety demo contained advice that went something like, "shortly after takeoff and before landing you will hear an airflow induced noise associated with the retraction and extension of the wing flaps. This noise is normal."Numerous PA about the condensation cloud from the a/c ducts, particularly in the tropics with humidity of 96% in the morning.
rallymania
(my bolding)
(at most fields, on short fields like LCY it's full flaps)
(at most fields, on short fields like LCY it's full flaps)
Last edited by Capt Claret; 27th Nov 2006 at 06:24.
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nope you are correct, that was my mistake... again
i'm about ready to put my blindfold on and go and play in traffic i've been so badly wrong here....
thanks for all your input folks, it's cleared up a big "mystery" and now i have what i came here for... the truth!
i'm about ready to put my blindfold on and go and play in traffic i've been so badly wrong here....
thanks for all your input folks, it's cleared up a big "mystery" and now i have what i came here for... the truth!
Fortunately for the rest of us, Claret never flew the RJ and therefore didn't experience it's awesome power, including the ability to take off at Flap 33. Come to think of it, neither did I (takeoff in the RJ at Flap 33! Second segment not too flash with Flap 33 at 2000ft AMSL and 44°C...). 
Ahh, a reason to watch the pommie olympics at last! I'll have the volume on the tellie turned up...
The retraction noise is quite audible from the station platforms and presumably will be from the Olympic Stadium alongside as well; listen out for it from anywhere in the world when watching the 2012 Olympics and see if the commentators notice it !
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while we're on the subject of the RJ100 and London City, I was on a BA Connect EDI-LCY flight at Easter this year which turned back to EDI about 25 mins after take-off. Pilot said that a fault had developed which meant that we couldn't land at LCY - but could land quite happily at any other airport.
I wondered at the time what kind of fault this might be... and also whether it was more about the difficulty of fixing it at LCY (or maybe the difficulty of taking off from there later to get it fixed elsewhere) than not being able to land there.
Any thoughts on what sort of fault might lead to this ?
13Alpha (just an interested PAX)
ps BA Connect handled it very well, had another plane ready for us pretty soon after landing back at EDI.
I wondered at the time what kind of fault this might be... and also whether it was more about the difficulty of fixing it at LCY (or maybe the difficulty of taking off from there later to get it fixed elsewhere) than not being able to land there.
Any thoughts on what sort of fault might lead to this ?
13Alpha (just an interested PAX)
ps BA Connect handled it very well, had another plane ready for us pretty soon after landing back at EDI.
When I flew the RJ there was a company SOP that you couldn't land at LCY with a FADEC out. It sounds as if this was probably a case of FADEC failure after departure.
I believe that ruling has changed in recent weeks.
(Moku you beat me to it by the second judging by the post time!)
I believe that ruling has changed in recent weeks.
(Moku you beat me to it by the second judging by the post time!)
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WHBM is just about correct...The noise you heard is probably aerodynamic noise at the wing to fuse joint. As far as I know the mod developed by BAE was a shutter device at the wing-fuse joint dragged up and pushed back down by the flaps. This 'retractable shutter' removed the aerodynamic gap the inner flap carriage made in the wing to fuse area as the flaps changed position.
As far as I'm aware it was only fitted on the 300 series aircraft. Maybe you were on a 100/200 series. Next time you get off have a look for it as its quite obvious under the flaps at the wing-fuse joint.
Bodjit
As far as I'm aware it was only fitted on the 300 series aircraft. Maybe you were on a 100/200 series. Next time you get off have a look for it as its quite obvious under the flaps at the wing-fuse joint.
Bodjit
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One drawback to it, I was told, is a common oil supply for engine and accessory case. A damaged accessory will spread FOD throughout the engine, making for some expensive repairs.
Pacific Southwest Airlines was the first to fly more than a couple of BAe-146: 24 in all. It was known as the "Killer Bee," or "Bring Another engine." They had so much practice changing engines, they could do it in 45 minutes at the gate.
Interestingly, the A320 has a similar sound as the 146 on approach at about 3,000 feet and below.
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146/RJFlap 'Hoot'
The sound is caused by the airflow entering the wing to fuselage fairings. Several attempts where made in the early days to help prevent this happening.The noise is there all the time the flaps are out it just reduces as the flaps retract or increases as the flaps extend.
It was originally thought that shutters on the flap track in the fairing would cure it, but as discussed it didn't. There was a fix developed which involved fitting small wedges on the inboard lower trailing edge of the wing, perfect, stopped it instantly. Only trouble is it induced a very low frequency vibration which made the test crew sick (it was a very unpleasant sensation)
I seem to remember that the 1-11 suffered from a similar noise when the engines where throttled back for descent before landing.
DC
It was originally thought that shutters on the flap track in the fairing would cure it, but as discussed it didn't. There was a fix developed which involved fitting small wedges on the inboard lower trailing edge of the wing, perfect, stopped it instantly. Only trouble is it induced a very low frequency vibration which made the test crew sick (it was a very unpleasant sensation)
I seem to remember that the 1-11 suffered from a similar noise when the engines where throttled back for descent before landing.
DC
Another 146 noise
Seeing as we are discussing the 146's little aural foibles here's another.
One day we turned finals into Edinburgh (Air UK) and the gear was extended. Now if you have ever sat directly over the main gear in a 146 you will know that when it goes out it makes a noise and thumps comparable to a whole lot of railway wagons being shunted together.
From the seat row behind :
"Oooh granny, what's that noise".
"Well I don't really know dear. I wonder if it's all the suitcases falling out from underneath".
It's 15 years on but I still am reminded of it, and smile, on each 146 approach.
One day we turned finals into Edinburgh (Air UK) and the gear was extended. Now if you have ever sat directly over the main gear in a 146 you will know that when it goes out it makes a noise and thumps comparable to a whole lot of railway wagons being shunted together.
From the seat row behind :
"Oooh granny, what's that noise".
"Well I don't really know dear. I wonder if it's all the suitcases falling out from underneath".
It's 15 years on but I still am reminded of it, and smile, on each 146 approach.
