A321 noises at take off

Darwin

Hope this doesn't come across as a stupid post, but I was on an EI A321 flight recently (St Dervilla iirc) sitting in 11B. There was a most curious noise on the initial climb out that persisted for about 5 to 10 minutes - a sort of reasonance/whining that got progressively louder and then stopped all of a sudden for the remainder of the flight. The noise did not seem to be related to the engine load. Now I've had quite a few flights over the years on the A320 and am pretty familiar with the usual 'hydraulic' sounds but I have never noticed this type of noise (on the A320) given that I usually sit around the same place. Is the A321 normally this noisy at departure?

L1011

Have had a similar set of noises on an older EI A320 (can't remember the reg/name at all; just remember it having the buttons for the announcements...). The A321s are relatively old so it could be something to do with that era of plane.

bkehoe

Most likely the wing landing lights. They can produce quite a resonance on some aircraft and not linked to age at all. I was on a brand new A319 recently on which they were really obvious. Because they swing downwards into the airflow they disturb what is normally smooth airflow beneath the wing.
Generally most company SOPs would have the wing landing lights switched on below 10,000ft which is why the noise ceased soon after departure.

sunnysoutheast

A while back Aer Lingus used an A321 on the early morning Cork-Heathrow flight. One of these machines often had a strange metallic whine from the port side emergency exit (which is a larger door on the A321) on climb and initial approach (i.e. when circling Heathrow). We did ask the crew once and her reply was that "it always did that"!

I always assumed it was something to do with a resonance of the door during pressurisation changes, but it could have been a light I suppose!

I never heard the same noise on anything other than an A321 and I've been on an EI A32x twice a week for three years now!

SSE

Su Campu

bkehoe wrote: »

Most likely the wing landing lights. They can produce quite a resonance on some aircraft and not linked to age at all. I was on a brand new A319 recently on which they were really obvious. Because they swing downwards into the airflow they disturb what is normally smooth airflow beneath the wing.
Generally most company SOPs would have the wing landing lights switched on below 10,000ft which is why the noise ceased soon after departure.

Sorry, I'm confused. Are you saying the lights actually physically move down when switched on?

Growler!!!

Su Campu wrote: »

Sorry, I'm confused. Are you saying the lights actually physically move down when switched on?

https://www.honeywellaes.com/servlet/com.merx.npoint.servlets.DocumentServlet?docid=DPHA4YQNGL0N77SIYR7W0IUXVK1562LEK

Tenger

There's something I didn't know when I got up this morning...........

sparrowcar

News to me too...and just when you have your "know it all cap" fitting firmly

Stovepipe

Immediately after take off, the undercarriage will be brought up and this takes about 40 seconds and uses two pumps and a linking device known as a PTU, all of which are very noisy, apart from the thumps of the doors opening, closing and locking after the gear has gone up. As the climb progresses, the pilot will reduce flap in stages, still using the same pumps and PTU. At the same time, the air conditioning packs will be busy pressurising the hull and they have plenty of valves, pumps and ducts and they make plenty of noise so there's a lot for the punters to hear, not to mind transmitted vibration from the airframe and engines. The predominant noise therafter is fan noise. You'd have to have wonderful ears to hear the landing lights motoring in and out,too, over the rest of the noise.

regards
Stovepipe

L1011

I'm used to the undercarriage, A/C, etc noise. Whatever I heard on the plane that day wasn't the usual noise.

It was, however, bloody cold where we were going to (Dublin was warm-ish, Manchester had fresh snow) so it might be something to do with the bleed air to the wings or something? It did stop a few minutes after takeoff though.

cml387

Often at a particular seat I can hear a louder buzzing noise than usual.I always put it down to resonance vibration.
Blaming it on retractable landing lights is a new one on me.

Plowman

This post has been deleted.

*Kol*

Plowman wrote: »

This post has been deleted.

The landing light is on the bottom of the flap fairing so if it didn't extend it would point only downward and not forward as they need it to.

bkehoe

Stovepipe wrote: »

You'd have to have wonderful ears to hear the landing lights motoring in and out,too, over the rest of the noise.

The OP was not referring to the motor of the retractable wing landing lights. He mentioned the resonance.

The landing light resonance is so well known that even an A320 full flight simulator replicates it.

Stovepipe

@myob, it could have been wing anti-ice valves cycling open and shut. AC has a mind of it's own. Faults that the pilots and cabin crew report can't be reproduced on the ground and clear themselves on the MCDU so we end up writing "no fault found" in the log, which drives them mad and sets up a round of complaints and finger-pointing until the AC pulls another trick the next day:)

regards
Stovepipe

Suits

I dont have huge amount of type specific knowledge of the a321 but any chance the aircraft was expediting a climb and so the engines were at a power setting higher than usual?

Darwin

The captain did promise to make up time enroute as we were delayed by 10 minutes, but the noise continued after I could hear/feel the engine thrust reduced during the climb phase. The landing lights explanation sounds very plausible (it was a windy day) and if they were retracted at 10K feet, that might explain the noise for that period of time.

Su Campu

Darwin wrote: »

The captain did promise to make up time enroute as we were delayed by 10 minutes, but the noise continued after I could hear/feel the engine thrust reduced during the climb phase. The landing lights explanation sounds very plausible (it was a windy day) and if they were retracted at 10K feet, that might explain the noise for that period of time.

Doesn't matter whether it was blowing a gale or dead calm, to an aircraft in the air, wind does not exist in that sense.

Immelman

It's the tips of fan blades going supersonic as air passes through them. Sounds like a chainsaw. BTW completely normal

*Kol*

Here's a photo of the landing light of a B737 (in retracted position) for anyone who is interested.

John_Mc

It's required to have your landing lights on below 10k but at least on the 737-800, the pilots are able to retract the retractable lights and leave on the fixed lights.

Does the A320 not have this as well?

bkehoe

John_Mc wrote: »

It's required to have your landing lights on below 10k but at least on the 737-800, the pilots are able to retract the retractable lights and leave on the fixed lights.

Does the A320 not have this as well?

The 320 only has the wing (retractable) landing lights and a separately switched light which is on the nose landing gear for Taxi/TO which is hidden away in the wheel well once the gear is retracted (along with the sideways facing turnoff light, separately switched as well). Switching the nosegear lights on/off is part of the flow after gear extension/retraction but the wing lights only at FL100.

And you cannot have the landing lights on while retracted as the switches for the wing lights go from the Retracted - Off - On positions. You can have the lights extended but switched off if needed temporarily for various reasons.

A320

*Kol* wrote: »

Here's a photo of the landing light of a B737 (in retracted position) for anyone who is interested.

Ah the B737 Classic o/b landing lights,what a pain in the arse,at least the NG ones are in the belly