Runway deceleration?

[dochealth]

On EI A319 from LHR yesterday. Twice during take off roll the a/c decelarated briefly. We eventually took off normally albeit towards end of runway...
I'm curious as to what may have caused this?

[Radix]

............

[dochealth]

Thanks Radix. It was not especially windy. But thunderstorm activity in the area earlier.
And yes you are right it was brief loss of acceleration rather than deceleration.

[Doors to Automatic]

Was the aircraft full? Either way it would be relatively light due to short sector length and operating off a very long runway so the power would have most likely been de-rated making the perception of acceleration changes greater.

Rest assured there would have been plenty of extra power available if required!

[BOAC]

"would have most likely been de-rated making the perception of acceleration changes greater." - ??????

[jackieofalltrades]

Maybe it was a learner pilot having problems with the clutch whilst changing gears...

[BOAC]

I'm sure Aer Lingus ABs are all automatic gearboxes, are they not?

[CISTRS]

Maybe it was a learner pilot having problems with the clutch whilst changing gears...

Lack of traction from the driving wheels? Maybe a slick runway? :rolleyes:

[TightSlot]

Blocked Carburettors and diesel - never changes

[PAXboy]

Well, if they WILL buy their fuel from Tesco ...? :=

[Radix]

............

[BOAC]

Radix - you'll be OK - it was an AB319. The 787 has electric motors, I think, so no clutch?

[belfrybat]

Maybe the conveyor belt bearings are worn out.

[PAXboy]

Being reminded that it was a 319, I realised the REAL reason - the pilots got distracted by the barking dog. :eek:

[S.o.S.]

dochealth Thank you for giving such an opportunity for diversion from the main flight plan (terrible pun intended) please don't take it personally!


Further suggestions are welcome.

[Radix]

............

[timtrb]

Hit a puddle!

[OverRun]

The runway is a bit rough and it was the pilot's foot bouncing off the accelerator pedal briefly.

[dazdaz1]

I'm not a pilot nor have a great understanding of a/c flight systems. I always presumed commercial jets had leavers, when pushed forward the thrust would increase. I never knew some AB models have accelerator/thrust pedals.

I have one concern about the thrust pedal, on a long flight does the pilot have to keep pressure on the pedal as one does when driving a car?

[DaveReidUK]

I have one concern about the thrust pedal, on a long flight does the pilot have to keep pressure on the pedal as one does when driving a car?

No, there's a cruise control for that.

[G-BPED]

"I have one concern about the thrust pedal, on a long flight does the pilot have to keep pressure on the pedal as one does when driving a car?"

They have a piece of wood to wedge between the pedal and the front instrument panel :}

[ExXB]

I believe some of the 'posh' airlines have 'cruise control'! :\

[blaggerman]

I believe that on some EI A319 the external inertial dampeners are manually configured, and sometimes the crew forget to disengage them until they attempt the takeoff roll leading to some momentary head scratching.

[Capot]

Just as a point of interest, dazdaz, most commercial jets have leavers, but these normally only spring into action after landing. There have been exceptions, but to do it in flight takes nerve and special equipment.

[PAXboy]

It is true, ExXB, that the posh airlines have cruise control but it's a little known fact the poorer airlines use child labour. :eek:

In the days of the British Raj, there was the Punkah Wallah, who kept the fan going steadily at cruise speed. Now there are Cruise Wallahs.

The child crouches under the dashboard (as the flying people like to call it) and when the pilot person shouts, the child presses down on the pedal. Woe betide the child who sneezes during take off and let's the pressure up for even a second. :uhoh:

[dazdaz1]

I'm on a EZY flight next week, usually a 319 I'll ask one of the pilots at the gate does his/her 319 have cruise control for the thrust foot pedal.

[twb3]

Pull the other one, it's got bells on it.

[Togue]

Perhaps they forgot to change the spark plugs during the last maintenance check.

[Basil]

All of you, taking the piss:

http://images.yuku.com/image/gif/00a2524c7a191de483c44c74a886df8c7ca21fa.gif

[skyhighfallguy]

to the original poster:


there are conditions akin to windshear which will cause a plane not to accelerate. Severe enough these are good reasons to abort (we now say: reject) the takeoff.

I can't speak for your exact plane's situation. IT is important to note that we in the cockpit have instruments to help us know how the acceleration is going.

how did YOU know? just seat of the pants? It does sound like a bit of wind shear, but that acceleration was ok and takeoff continued.

Although those planes do slip a little in second gear :-)

I once had a locomotive engineer (train driver) speak to me in the boarding area, he asked how the power got from the engines (in back) to the drive wheels.

I told him we use the shopping cart method. You just push the thing and it rolls. It dawned on him there was no connection to the wheels from the engines. We had a good laugh and remarked that the F7 diesel locomotive looked a great deal like the front end of a 737.

it is important to the original poster that you understand we need AIRSPEED to fly. You can only, at best, feel (sort of)
groundspeed on the runway.

Hey, next time something feels funny, after you land, ask the pilot.

[notjustanotherpilot]

I don't know about anywhere else, but in Australia in the time since 2001 and increased paranoia, as best as I can recall whenever I've flown as SLF the pilots have been onboard and locked away well before the pax load and maybe once have I seen them before the pax have all gotten off - I'm usually in cattle class and in no hurry to get off unlike most others, and quite often tend to be one of the last if not the last SLF out the door, so being able to talk to any of the flight crew is not an option.