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-   -   Why start right engine first? (https://www.pprune.org/tech-log/61802-why-start-right-engine-first.html)

Firestorm 8th August 2002 18:03

SF 340.

Left engine first for a GPU start because of reasons given by BH, and because the GPU is usually just behind the right engine, thus running the risk of frying the ramp rat as he unplugs it.

Right engine for a battery start, becase the batteries are on theRHS, so less voltage drop between battery and engine. Also, some aircraft have a prop brake on the right engine which allows it to be used as an APU for electrics and heating (as well as other services) on stand.

HotDog 9th August 2002 05:01

In a previous life, our start sequence on the 747 was 4, 1, 2, 3. Because of the idle thrust of these engines, if two engines are started on one side first on a wet or slippery tarmac, the tug has great difficulty in controlling the aircraft during pushback.

BEagle 9th August 2002 05:55

3,4,2,1. Because that's what they did on Lancasters.....

Watched the start up of a B-52 once - levers all over the place as 2 pilots started a seemingly random selection of the 8 engines each!

Original V-bombers could start all 4 simultaneously, put all the gennies on and switch all the electro-hydraulic PFCUs on - all at the same time!

BlueEagle 9th August 2002 10:42

Remember seeing a line of Vulcans one day, all quiet one minute then BANG! they wound up in no time and taxied immediately.

From first start to last airborne could only have been a few minutes. Really impressive to watch.

spanner-do 9th August 2002 11:10

From a techie point of view

On our Boeing Fleet

We recommend starting the #2 first especially if using a ground (air) cart. This is because it allows for additional safety in the event of Starter Cutout failing to operate as advertised. There will be at least one isolation valve in the pneumatic system which can be closed to shut-off the air supply to the starter.

The ground cart feeds into the left air supply system.

Divergent Phugoid! 9th August 2002 11:27

Would it be cos the pilot cant see the right one,but if he or she starts it first he/she will be able to hear it running, where the left he/she will be able to chuck a look over their shoulder????





:D ;) :rolleyes: :D

PAXboy 9th August 2002 17:04

With regard to the V-bombers being able to crank all four together .... that would have been something to see - actually to hear. :D

As to the bod at the front being able to look back and see what was happening on the wing, is this not another reason for the video camera tucked under the rear fuselage? The point of that was from the BD problem of shutting down the wrong engine but it might also help with starts, i.e. seeing the puff/cloud of exhaust from a jet or watching the spokes go round?

The idea being a camera in a faired pod under the tail, so that it could see wing tip to wing tip. The image would be viewed on one of the glass screens by the mode selector. The camera would be able to see the undercart and it's doors, the engines and the flaps and other flying surfaces on the wing. In the event of dumping fuel, you could (probably) see it streaming away from the vent.

This was also mentioned with the problem of some carriers no longer having ground staff available for inspection of the flying surfaces response to input. Particularly so on the first rotation of the day, or after maintenance.

BEagle 9th August 2002 17:41

Never flew a Vulcan when 'Mass Rapid' starts were allowed - but we still had the 'combustor' facility on most of them in the late 70s. You parked the throttles at the 50% position, selected rapid start and pressed the 4 start buttons in succession. An uncontrolled fuel/air explosion in the engine combustors spun up the engines in no time at all, as soon as they'd started and the gennies were on you started the PFCUs, 8 seconds later they'd all be running. You briefly cycled the throttles back to idle, then selected full power, turned left a few degrees off the ORP and thundered down the runway. 10-15 minutes later you'd be passing 40 000ft, still climbing...

Mark you, we've done crewroom to airborne in 7 minutes in the dear old Vickers Funbus - most of which was in the bus getting to the aeroplane!

PAXboy 9th August 2002 19:39

Hi BEagle, the Mass Rapid Start sounds like big fun. Pardon my ignorance of nicknames but what was the Vickers Funbus?

BEagle 9th August 2002 21:30

RAF VC10K. Because it used to take us from one fun place to another.

Rarely these days though........

PAXboy 12th August 2002 05:10

Ah, I wondered if that was what you had in mind. The first aircraft I ever travelled in aged nine, the original VC-10 on a LHR ~ JNB with a fuel stop in NBO. Later we had the Super VC-10 on that run.

In it's BOAC livery, it was simply the most beautiful machine in the air. If I catch sight of one now, perhaps when motoring on the M4 near Swindon, it is enough to endanger the car and my passengers!

78deg 12th August 2002 15:55

On B757

It is nessesary to test the PTU before all TOs this is accomplised by Right then Left.

Flight Detent 12th August 2002 18:35

Hi SPANNER-DO,

I find your reasoning quite interesting!

Do you recall that there are, in fact, two pneumatic valves that have to be opened to supply air to the engine starter,
1/ the start control valve, the one you mentioned may malfunction, and
2/ the pylon valve, the one that opens to allow pressure to the start control valve, the one that will only allow reverse airflow, ie, towards the start control valve, when the FE selects that engine to 'ground start'.
Both close, at the same time, when the starter is released.
The isolation valves are not normally used here.

Actually, 4,1,2,3 is the best start sequence of all, taking system operation into account!

Cheers.

747FOCAL 12th August 2002 19:46

Usually only one engine has a hydraulic pump that can start it after that the lit engine starts the rest. Cept inflight then you can windmill and get them going again.

spanner-do 13th August 2002 11:32

Hi Flight Detent

Thanks for your response to my previous posting; in which I was refering to the original thread question of why start right engine first then the left as "Glonass" had asked.

I made the assumption (right or wrong) that we were referring to twin engine beasts.

My response was relating to our 752 and 763 fleet.

Sorry for the confusion.

Regards

Spanner-do

Mago 13th August 2002 15:36

IMHO
 
Talking about my experience, when I flew light twins (some of them) I started the left engine first when there were daylight and I started the right first when it was dark, because in the nights I couldn’t see prop when it kicked and start playing with the levers, so I had to do it by hear. I preferred to do that because when you start the right first, the passengers used to get scared faster.


When I flew B727 as a F/O, we started 1,2,3 or 3,2,1 depending on the mood, unless we where pushed back with a turn, so we started first the engine inside the turn to help the tug, especially on rainy days.

Now, on the ATR I started the Nº 2 first because it has the prop brake, so it is like starting the APU, nevertheless I (SOP) do not release the prop brake until Nº 1 is stabilized.


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