KARFA

Didn't need the autoland in the end. We use active sky so that gives us real world weather. Landed 09L at 0545. RVR was 5000 so fine and only a bit of haze. Only issue was the low cloud at 700ft which meant we couldn't see the runway until relatively late. Planned for a CAT III and then did a CAT I reversion once visual. Stand 518 which was very convenient for the next crew who were departing 09R

You are just showing off now

T8191

Lets just say that back in the slightly less stringent 60s, it was not uncommon when reaching 'break-off height' on GCA at around 250' to receive a very crisp "Keep talking" from the pilot

Globaliser

At LCY last week, our APU failed so we could not self-start the engines. We were told that the fix was to do a cross-bleed start. Presumably the whole story was that one engine would be started with ground power, and then the other with a cross-bleed start?

The more interesting thing was that we had to be towed off our stand near the western end of the apron, and parked on stand 23 at the eastern end, before this could be done. Why would this have been? Why couldn't the ground power / cross-bleed start be done at our original stand, or indeed any other stand?

KARFA

Here is the relevant page from the QRH - it is for a 737-800 but the principle should be the same:



You need both ground power and ground air to get one engine running. Ground power on its own is not enough. Once you have one engine running you can start the other from the first engine and you no longer need the ground power or air.

Perhaps at LCY the ground air unit is only available at stand 23?

flatlander

The clearance behind aircraft on stand (which park nose-out from the stands at LCY) near the terminal is not great, perhaps it is not sensible to run the engines above idle on stands near the terminal building.

Heathrow Tower

Autolands can be used with MLS.

Waterhorse

As KARFA has has explained we need both ground power and air to start an engine without the APU. The "starter motor" on a jet engine is really only air - the air is used to spin up the rotating sections of the engine which provides the air part of the fuel air mix that gets burnt, the fuel is added and a spark is added and voila, engine start.

The addition of fuel and the spark requires the ground power. To crossbleed, ie take air from one engine and use it to start the other requires increased thrust from the running engine, not a massive amount, usually c 30% rotation speed on the main rotor but even that will provide a strong efflux and needs space.

We do sometimes start one on stand then push back and crossbleed but you will notice when we do that we push all the way onto the taxiway centreline before starting the second engine, all to avoid excessive jet blast.

Globaliser

That makes perfect sense - thanks to both of you (and to KARFA).

PETER01

A wee query for BA crew from Stewie Mac

It was in another thread but thought it would be best posted here.

TrainDriverSparky

What is the maximum altitude/service ceiling of the 744?
G-BYGB that was meant to operate the BA192 DFW-LHR on 07/11/15 but sustained fanblade damage appears to have flown at 45,000ft for a portion of the flight while positioning back to LHR as BA9172.
Flightradar24 data.
Is it possible to fly at higher altitudes without the weight of passengers and their bags loaded?

Globaliser

Yes, although 45,000 feet is pretty much it for a 747: http://www.flyertalk.com/forum/briti...l#post25426754

TrainDriverSparky

Interesting. Thanks for the link.
I assume the benefits of being higher are that the air is thinner and therefore there is less air resistance/better fuel efficiency?

ATCO2

Fuel efficiency does improve at the higher levels yes. Although flying at a lower level than optimum for fuel purposes for a given a/c weight might give the benefit of avoiding headwinds or taking advantage of tailwinds.

Waterhorse

Max alt can also be limited by the fatigue caused by pressurising the hull. The greater the altitude the greater the differential pressure required to maintain a sensible cabin altitude. There may be a small difference but this over many cycles can add up. SH Airbus' are limited to 39000 as mentioned the 744 to 45000. With SH the advantages of climbing to the higher cruise levels is seldom enough to warrant the fuel to climb there.

mlv416

I am hoping this question isn't too boring, but do any FA's know if the C.A.R.E.S. Amsafe harness can be used to fly on Premium Economy or Business Class seats on the YYZ to LHR route? Seems like the plane will be a Boeing 787-8 or 777 there and back if that helps?

And then even further on regionally from LHR to BSL? Then an Airbus319 there and back if that helps?

If not, then while my Clek Fllo car seat fits in width, I am worried it doesn't fit in the other dimension for both these flights of 17.5" by 17.5", which seems so small?

I do not want to check my car seat under any circumstances, but will I be able/allowed to fly with my 2 year old with just a lap belt if the C.A.R.E.S. harness doesn't work - I am guessing yes?

Any insight is appreciated. Thanks!