Why start right engine first?
 

I wonder why the engine start sequence is right first and then left. Is this the sequence you apply as well for you airplane? And why?

Aircraft are designed with passenger doors on the left. As these doors are still being closed and other personnel in the area, starting on the right allows the f/c to (literally!) get started.

By the time the right has run up and stabilised, ground staff will have cleared the area.

I sit to be corrected.

it depends.

the 320 starts the right engine first. the 330 starts the left first. it is all to do with which engine powers which hyd system for the brakes.

SAAB 340 left engine first. Electric start and battery at left wing root giving least voltage drop on start.

On the 737s, always the right one, same reason stated by Paxboy, unless if there is no APU bleed pressure for engine start, in that case no 1 must be started first!

From a "light twin" perspective, I've mulled over at least five different starts....for different aircraft....


Left first - because you can see the prop area is clear from the pilots seat...

Right first - because it's nearer the battery (aircraft specific)...

Left first - because it's furthest from the passenger doors and emergency exit (aircraft specific)...

Right first - because it's furthest away from the passenger doors and emergency exit (aircraft specific)

Alernate first start - because it then allows you to listen to the noise of each individual engine, at different times, without the noise of the other one running...

We have yet to mention the idea of "because it says so in the POH".

Well, thank you all for your prompt replies.

The fact that the engine powering the brakes system is started first is an interesting perspective. At least that technical explanation satisfies me.

PAXboy, your statement is correct but I believe that would apply to some type of aircraft or operation, at least, on most jet aircrafts, the doors are usually closed previous to engine start.

Regards,

'Way back when, some twins only had one hydraulic pump - on the right engine - thus the 'start right first.' Four engined aircraft had two pumps, one each on engines two and three, but the entry door was on the left, thus start number three first, followed by two, one and four.
Some twin turboprops I've flown recommended alternating starts between the right and left engines, just to verify that the de-icer boot suction was working from that engine. If you intend to start any engine out of normal sequence, make sure the ground crew knows about it. :)

Left on SF-340? At the airline I worked for it was always right first. For pax loading, as stated above. That way you could get the cabin nice and cool (or hot) before people got on board.

Right first, get the A/C up and running for the VIP's, and they are not blown away getting on board.

In the bugsmasher world, it's difficult to hear the rh start to fire when the left is already deafening you.

That's my excuse...

However, type specific procedures may change this start order.

1. The POH says to

2. Habit

3. Variable depending on if I want to monitor one engine's output before the other contributes it's bit eg suction

Glonass,
That is true but I was thinking of the 'generality' of starts. Admitting of course that Pax cannot always be sure which is starting first. Other than by timing and knowing the typical sequence when a route or carrier is used often.

In the winter it is easier as there is often a more distinct cloud of exhaust from a cold engine than from a warm one in summer. Also, if occupying a window seat towards the rear, the sound of start will be distinct. It is then possible to judge by the other activity or push back, whether it is 2 ~ 1 or 1 ~ 2.

I was also thinking about regional airports and aircraft, where a jet bridge/air bridge is not available/used. In this case, ground staff are likely to be clearing the stairs, chocks and so forth. Also, if air stairs are in use, they take a short while to stow. If they can get the No 2 engine started, this might gain a full minute (or more?) on the sector time.

Glonass

On the BAe146 the park brakes are powered by #2 engine, with electric hyd pump back up. The #3 eng provides the second hyd system power with PTU backup.

Pax load from the left and baggage & fuel on the right.

With engine start commencing after doors and stairs removed, start sequence in my co is #4, #3, #2, #1, simply because that's what every one expects.

If pax still boarding or head count still in progress but baggage doors closed, then start #4 & #3 to assist on time departure, or reduce delay, or if APU U/S, provide some aircon.

If pax on board and stairs removed, with approval of baggies, will sometimes start #1 & #2 first, to minimise delays.

If at an aerobridge, always start right first as they're furthest from the aerobridge.

It's all very fluid depending on the circumstances and I can't think of any reference that says 'thou shall start in this sequence'.

In my last company, on the B744, we started 1,2,3 & 4 if possible. System 1 gave us Alternate Brakes whilst system 4 (Aux - and electrical, already selected 'on' before start),) gave us power to Normal Brakes. 2 next as that also supplies alternate brakes. System three is the least important on the ground and #3 was the engine to be shut down first if extended taxying/waiting was expected. #4, (Normal Brakes), would be last as we had not started to move under our own power yet.

Often, at out stations, an engineer unfamiliar with our companies start sequence would clear us, "4,3,2 & 1" but this was normally only in Europe.

In my company on the 744, we tend to start 4 3 2 1. It doesn't matter on the 744 as the brakes are powered by the aux pump number 4 and the body gear steering for pushback from aux pump number 1. If we are starting on pushback, we tend to start the engines on the inside of the turn first to give the tug a chance.

But I can see the logic in starting the right first normally. Sucking the passenger into the engines can be bad for business.

Don't know if they still do it but the P&W powered B777 starts both at the same time. Must have a mega APU. I have seen United do this at LHR a few years back, don't know about the 777 engine types.

Hi all,
With the Classic B747, which I believe is the same, systems wise, as the -400 -:
Firstly, prior to pushback, the FE pressurizes the #4 hydraulic system with an electrically driven pump, for the aircraft brakes to work.
He also pressurizes the #1 hydraulic system with the Air Driven Pump (ADP), to power the body gear steering during the push.
Which also acts as a back-up brakes system for #4, (FE selectable), should it fail!
Even though we do start 4,3,2 &1, I've been trying to get our people to change to 1,2,3 &4, because:
#1 has the ADP running, using bleed air from the APU, which could be better used to wind up the engines a little better, especially with some of the, slightly used, APU's. Once #1 is running, the EDP output will 'auto-off' the ADP, thereby providing better bleed air pressure for the other three!
I think, in QF Classics, after #1 is started, with now no ADP running, they turn on one aircon pack during the starting of the others, but they seem to have better quality APU's than most!

Cheers

At my company, on the A-320, we start the left or #1 first, fwiw!

More Aircraft specific stuff - AC50.
 

Fot the Shrike, well the battery is behind the wing in the fuse, so the voltage drop difference via distance is negligible.

Usually alternate starts to check if the hydraulic pumps on each engine are working.

Unless it's hot when I always start the right first as that has the aircon running off it... :D :D