Fear Of Flying

[potty64]

My sister returned from France and was worried the plane was going to konk out becos the drone of the engine kept fluctuating. There was a continuous drone on the same 'note' and then it would sound lower but then resume the original pitch.Why is this?

[grasscarp]

Sounds like she was in a turbo prop aircraft. All quite normal for adjustments to be made.

[mazie]

Did she fly with Flybe by any chance potty? If she did, as grass says probably turbo prop.....

I'm the same... I hate it and I fly a lot to Edinburgh on a Dash 8.... Can never wait to get my feet on Terra Firma

[sandyRoe]

I'm far from being an expert here, but if the pilot wanted to maintain a constant speed he might put his foot on the accelerator and that would change the sound of the engines.

[grasscarp]

emm Sandy, no feet on accelerator! I used to fly turboprops. More likely
engine power reduced (by hand on throttle) and propeller pitch change (another hand operated lever).

[sandyRoe]

Ah, OK. But apart from the finer details of where the pilots feet are, was I on the right track?

[grasscarp]

whatever LOL

[potty64]

Hi EVERYONE! She flew with RYAN AIR. Are they turbo prop air crafts? And if so, why should adjustments have to be made?

[mazie]

No, I think they use 737's

[grasscarp]

Adjusting speed, climbing, descending, fuel flows, propellor pitch etc. You climb, level out, adjust the attitude etc, Get given a new flight level, descend (or climb) etc. There is a lot going on and the noise will never be constant throughout the flight.

[grasscarp]

OK - jets also need to make changes to power settings and pitch frequently due to reasons I tried to paraphrase in above post. Biggest thing I ever flew was the HS125 which is a business jet for around nine people. I never noticed the noise, but we were wearing headsets continually.

[EDDIE51]

It's when the engine noise stops that you should start worrying!

[grasscarp]

Correct Eddie. That is when the fear of not flying kicks in!

[mazie]

LOL... how very true Grass :o)

[EcclesCake]

I agree with everything (the vastly more experienced pilot than me) Grasscarp has said.

Another way of reassuring your sister that all is normal is to suggest she thinks about the note of the engine in her car. Going up and down the gears, accelerating, slowing down, manoeuvring, etc. with each variation the engine note changes and it is just the same for an aircraft.

[Canary42]

If the note changes for a short time then reverts as you suggest, then it's probably because the pilt receives intruction from Air Traffic Control to change height - if it stayed at the same height then a bit later the noise would instantly become very very very loud then stop altogether !

[grasscarp]

Canary reminded me of the joke (or it may have been true)
ATC: Ryanair 456 turn right 30 degrees....
pilot: wilco. can you say why we need to?
ATC: noise abatement
pilot: we are at flight level 300 (about thirty thousand feet) so how can it be noise abatement?
ATC: have you ever heard the sound of two 737s colliding?

[Canary42]

LOL

[Clanad]

I see Ryan Air operates the Boeing 737-800, so, technically, our instructor friend grasscarp is correct (never argue wit the instructors!) The 73-800(as it's known in the aviation world) is powered by the CFM56-7BE turbofan jet engines. Although it is a turbojet engine, it shares the technology of a shrouded fan in the front which is, by all definitions a multi-bladed propeller.

Seen here: http://www.cfmaeroengines.com/engines/cfm56-7b .


The noise change detected by the passenger described can be caused by a number of things, but impending engine failure is way at the bottom of a list of possibilities. If there was only slight turbulence, for example, the engines compensate for the additional or lessened air intake, compression, fuel burning and exhaust.

Additionally, the cabin pressurization system can be the likely culprit when describing noises and changes. Air is taken from just aft of the compression area in the engines (known in our profession as "bleed air") manipulated, cooled, heated, reduced in pressure and finally injected into the interior of the aircraft. This process probably accounts for nearly 50% of cabin noise.

All this is said to explain that both the Boeing 737 series (originally certificated here in the U.S. in 1967-1968) and its engines is one of the safest airplanes ever designed. The increasingly dependable engines used thoughout its lifetime are well proven. So much so that similar engines on other Boeing and Airbus twin engine aircraft have reached a milestone of being allowed to fly over oceans and Polar routes that only require a suitable landing field at one engine out speeds to be within 330 minutes (originally this ETOPS (“Extended Range Operation with Two-Engine Airplanes", was only 60 minutes).

Lotsa white knuckle fliers out there, but there's very little to be concerned about, other than locating the "Lav Occupied" sign...

[aelmpvw]

it's when you hear the pilot snoring that you should start worrying

[grasscarp]

Clanad, I was thinking about you when I mentioned my flying experiences - waiting for our resident "big gun" to see this thread!
I was never a flying instructor. My teaching is all on the ground and for airline dispatchers now. I didnt want to sit in a light aircraft while someone sat next to me trying to kill me .......