In videos I always see the hydraulic pumps turned on before the engine start.  Today I see a PMDG 777 tutorial by a real 777 pilot who turns on hydraulic pumps after the engines are started.  Do it make a difference in the sequence or when to turn on hydraulic primary and demand pumps?

FCOM NP.21.29 the hydros are brought on line before engine start, with the warning that pressurization should wait until after the nose gear is locked out.  I suspect the your "real 777 pilot" is following their company policies that restrict hydro until after engine start to ensure nobody gets body slammed with a loose tow bar.  My guess is it happened once and a manager made such a decision.

On 3/11/2018 at 11:10 AM, paulyg123 said:

In videos I always see the hydraulic pumps turned on before the engine start.  Today I see a PMDG 777 tutorial by a real 777 pilot who turns on hydraulic pumps after the engines are started.  Do it make a difference in the sequence or when to turn on hydraulic primary and demand pumps?

The normal sequence is to switch on the R demand pump first. Thereafter from right to left, CTR R and L elec pump, L demand pump, CTR demand pumps. the reverse flow applies after engine shutdown at the end of the flight.

 

the reason for this flow is to prevent HYD fluid transfer from the R HYD system to the Centre (if i recall correctly from my Ground School lectures).

 

There is one occasion where the ELEC HYD pumps were off until after engine start, that is the "ENGINE START on battery only" procedure. This procedure is detailed in the Supplementary Procedure of FCOM 3 section SP7 if my memory serves me correctly. The idea of shutting off most of the electrical stuff is to minimise the power loading on the aircraft electrical network until after at least one engine is running. 

 

 

Edited March 12, 20188 yr by Driverab330

I've seen it done at various times during the FLO - depends on GND PWR, etc.

I will (sneakily) pressurise R HYD system to dial in the TO trim before engine start (so I can tick the box on the ECL) - then OFF again. Then, just before P & S, I'll request of ground crew; "May we pressurise?", then, beacon on and the lot on - going anticlockwise from R HYD.

3 hours ago, ganter said:

I've seen it done at various times during the FLO - depends on GND PWR, etc.

I will (sneakily) pressurise R HYD system to dial in the TO trim before engine start (so I can tick the box on the ECL) - then OFF again. Then, just before P & S, I'll request of ground crew; "May we pressurise?", then, beacon on and the lot on - going anticlockwise from R HYD.

I wouldn’t be very happy as a ground engineer if the flight crew is pressuring a 3000 psi HYD system without letting me know in advance.... and any leak would be deadly. 

 

And who knows if any mechanics are cleared of the critical areas, the taxi camera doesn’t cover a lot of area. 

 

quite irresponsible as a pilot I must say.

 

 

Edited March 12, 20188 yr by Driverab330

20 minutes ago, Driverab330 said:

I wouldn’t be very happy as a ground engineer if the flight crew is pressuring a 3000 psi HYD system without letting me know in advance.... and any leak would be deadly. 

Assuming entirely that they're in the direct path of any fluid, which isn't really that common. Perhaps when placing/removing chocks? But even then, that's done when it's pressurized anyway, since the crew will need the brakes...so there's no real increase in exposure there.

To me, honestly, I feel that it's made a bigger issue than it really is. Does it increase risk? Yes. Is there a way to reduce risk? Yes, turn HYD off when it isn't needed. But does it need all of this ceremony? In my opinion, not unless you had maint out there. Beacon on? Okay, the rampies know to stay away from surfaces (they're taught to stay away from them anyway just in case, and they really have no need to be around them with the exception of RJs perhaps).

1 hour ago, scandinavian13 said:

Assuming entirely that they're in the direct path of any fluid, which isn't really that common. Perhaps when placing/removing chocks? But even then, that's done when it's pressurized anyway, since the crew will need the brakes...so there's no real increase in exposure there.

To me, honestly, I feel that it's made a bigger issue than it really is. Does it increase risk? Yes. Is there a way to reduce risk? Yes, turn HYD off when it isn't needed. But does it need all of this ceremony? In my opinion, not unless you had maint out there. Beacon on? Okay, the rampies know to stay away from surfaces (they're taught to stay away from them anyway just in case, and they really have no need to be around them with the exception of RJs perhaps).

Yes, I should have mentioned that the beacon goes on before any pressurisation.

Besides, my GSX ground lot flaunt health and safety on a regular basis; No ear protection, driving their wretched baggage carts through my main gear, crashing their fuel bowser straight through No 1 engine, etc.

7 hours ago, scandinavian13 said:

Assuming entirely that they're in the direct path of any fluid, which isn't really that common. Perhaps when placing/removing chocks? But even then, that's done when it's pressurized anyway, since the crew will need the brakes...so there's no real increase in exposure there.

To me, honestly, I feel that it's made a bigger issue than it really is. Does it increase risk? Yes. Is there a way to reduce risk? Yes, turn HYD off when it isn't needed. But does it need all of this ceremony? In my opinion, not unless you had maint out there. Beacon on? Okay, the rampies know to stay away from surfaces (they're taught to stay away from them anyway just in case, and they really have no need to be around them with the exception of RJs perhaps).

 

I must disageee with this having seen it in real life that HYD fluid spitting out on the main gear of a 773ER. 

Well, how hard is it just to say “cockpit to ground, we need to pressurise the R HYD to set the pitch, are we clear?”  5 second max I would say. 

When they know you going to pressurise the HYD they won’t usually go near the main gears and the brakes. normally they would only do so after they have seen you pressurise the HYD first and readying to push. 

On the airbus, the HYD would be pressurised as engine being started and with engine driven HYD pump cranked up, so unless you are starting one at the bay there is no such risk, and that’s why the airbus normal procedure (A330/350) does not require one to ask the ground crew “are we clear to pressurise” before pushing back. 

I guess the safety culture is quite different in the airline I work for, and the operating environment we have including flying to most places where people don’t normally speak fluent  English and common sense isn’t very common.

 

In addition, there are procedures to follow in cases like that when one feels that without the APU, they will overload the GND PWR system if they are going to start the engine with ground power only. So one wouldn’t need to sneakily turn on the R pump to in order to tick a box in the before start checklist.

 

Just do the battery start checklist in the SP FCOM3 and you are all covered without risking anybody’s life. 

 

Just a bit of sharing based on my operating experience on both the 777 and A330/340. And accident usually happen when people start to become complacent and taking shortcuts to procedures which was designed to safe guard against quite a bit of risk. 

 

 

14 hours ago, Driverab330 said:

I must disageee with this having seen it in real life that HYD fluid spitting out on the main gear of a 773ER. 

What are we disagreeing about here? I specifically noted that the gear is an exception. All the same, whenever anyone is going to be near it - placing/removing chocks - you're going to be under pressure. Pressurized fluid is going to cause some damage, and in any case they're going to be placing/removing chocks, it will be pressurized. It's implicit in the instruction, so why waste words? Stating that it's pressurized isn't going to stop it from causing damage.

*rush of fluid strikes person removing the chocks*
"Oh man. Glad the crew told me that things were pressurized, otherwise that fluid boring a hole in my skin would have caused damage!"

14 hours ago, Driverab330 said:

When they know you going to pressurise the HYD they won’t usually go near the main gears and the brakes. normally they would only do so after they have seen you pressurise the HYD first and readying to push.

As someone who worked ramp, I know this to be false.

On 3/12/2018 at 3:43 PM, Driverab330 said:

 

Well, how hard is it just to say “cockpit to ground, we need to pressurise the R HYD to set the pitch, are we clear?”  5 second max I would say.

 

I don't know what is standard at the airline you work for but at the one I work for the interphone is not continuously monitored by the ground crew and with all the noise on the ramp the they are  unlikely to hear the call horn so 5 seconds is maybe not a realistic estimate for everyone.

Edited March 14, 20188 yr by Ralgh

5 hours ago, Ralgh said:

I don't know what is standard at the airline you work for but at the one I work for the interphone is not continuously monitored by the ground crew and with all the noise on the ramp the they are  unlikely to hear the call horn so 5 seconds is maybe not a realistic estimate for everyone.

 

I apologise if this goes off topic.

I work for a legacy carrier based in a small city in South East Asia. And we don’t have any narrowbodies in our fleet. 

 

You are right the INT phone will not be continuously monitor but where I work and all online ports we go. When engineering prepares the airplane for departure, there is always a meachanic around within 20m from the nose gear. Places like japan / Taiwan, if you press “GROUND” on the 3rd CDU on the 777 or MECH on the overhead of an A330/340 someone will come and pick up the interphone in seconds. 

 

Even when we fly to the US / Canada, I never experience any problems at all.

 

The guys on Ramp uses a noise cancelling headset and a special micophone. Some of them are wireless others have a very long cable. So noise on the ramp is never a problem. 

 

Especially when we are about 10min from pushback they are always here with the tug connected. 

 

From where I work it is so easy to grab somebody as well, if you come to the airplane and find no one is able to help. Just ring ops within 5-10min someone will show up. 

 

Also, If you tell them when you get on the airplane say “APU GEN is inop today we need to start on ext GND power to start the engine” they will be assign someone there for you all the time. And a lot of time they are know the what problem the airplane has before arrival by reviewing the etech log through their Engineering software or their iPad, they will be very proactive to liase with you as to how to manage the departure setup. 

 

I guess this is the marked cultural difference from where I work and what other people had experience in other places of the world. 

 

To me, I am always able maintain a very close relationship to the mechanics and engineers and our company policy is so clear that no pressurise the HYD without letting ground know in advance. The ground guys too have a strict potocol to follow. 

 

The main point is, for those who had flown the 777/ airbus in real life before, if one follows the procedures propoerly and anticipate what they need to get the airplane ready to go, you wouldn’t need to sneakily pressurise any HYD systems. For example, If your APU GEN breaks down during your pre flight preparation, from where I work the engineer has to come to dispatch the airplane so you definitely will have a chance to talk to him before you need to do anything. 

 

Therefore the logic of “if the systems fails someone nearby is going to get injured anyway, therefore I should take no pre-cautions” sounds really odd to me. 

 

 

 

 

 

 

At my company....It's pretty simple, don't pressurized hydraulics unless it's verified that a tug is hooked up to the airplane or it's chocked. 

I don't understand why companies go through the lengths they do to try to write safety measures that cover every scenario possible.

It's assumed that the ramp environment comes with it's risks and dangerous hotspots. However, if both ramp personnel and pilots used common sense, accidents wouldn't happen. 

The odds of hydraulic fluid spitting oiut of the main landing gear is how much??? Probably super duper small.