Ask The Pilot

[BAM1748]

I havent seen this asked yet, Can a commercial passenger jet start and take off without the assistance of a ground crew? eg if you had to land in the middle of nowhere, and stop the engines, could you start and take off again?

Have flown through cities during coups, aircraft flies in goes to terminal and instead of to the gate does a u turn and faces outwards, drops and picks up and departs without assistance, I think they left the engines running but I was to busy running myself with head down to notice. :shock: (they even took their own baggage handlers on the flight who somehow got out to get some stairs, and they didn't worry about getting everyone seated before heading for the runway either)

Matt

 

[jb747]

I landed in SIN the other day on a Singapore 777-300ER and the pilot shut down the right hand engine for taxi. It was a long taxi about 8-10 mins with lots of stopping as well, but it was all right hand turns so imagine it was rather easy to turn right with only the left engine running.

And quite difficult to go the other way. How do you know that it was shut down?

I didn't realise the 747 had body gear steering. Very cool! Will pay more attention next time I see a 747 taxiing to see if i can spot it.

I don't know how noticeable it is from the outside. It only comes into play once the nose gear steering exceeds about 20 degrees, so it's only active for tight turns. It also deactivates as the aircraft exceeds 20kts, and reactivates once it goes back below 15kts. From the coughpit it's quite noticeable...even more notable if you have an aircraft on which it doesn't work, as they really turn like pigs.

 

[mjt57]

The 767 was always manual starts, and in that we'd wait until 'max motoring' (the fastest speed the starter could spin the N2/3 to)

Our gas turbines' starters were air driven. We had a high pressure (3mpa) system with huge air receivers to start 6 engines. Sometimes, if an engine failed to start, often due to flame out or compressor stall after ignition, there'd be some time before enough air pressure was built up again.

And given that the Trents are far bigger engines than what we had (they were around 737 size), I have to wonder at the requirements to spin them up.

 

[Harpoon]

And quite difficult to go the other way. How do you know that it was shut down?

By the noise. We pulled off the runway, and then came to a stop at which point there was a definite engine shutdown noise and my ears told me it came from the right hand side quite obviously. Of course I have no proof, but I would have put my first born on it purely based on the sound.

 

[jb747]

A new video....Melbourne to Singapore in 4 minutes - YouTube

 

[jb747]

By the noise. We pulled off the runway, and then came to a stop at which point there was a definite engine shutdown noise and my ears told me it came from the right hand side quite obviously. Of course I have no proof, but I would have put my first born on it purely based on the sound.

I don't think you can base very much on the sounds that you hear. Your comment would imply that if they did shut it down, then they didn't wait for the cooling period...which is very bad. The only reason you should shut down without doing so is an overriding checklist requirement....

I'll ask about it, but I would be extremely surprised.

 

[Harpoon]

Fair call, and you'd know not me! But it sounded exactly like the shutdown at the gate, except on one side.

 

[Simo]

Hi JB 747,

Just done QF10 overnight and we had a pax who spent a fair while on a oxygen bottle.

If they would have had to divert it to an airport for a medical emergency it would be very hard to find many airports that you could land an A380 at and then take off as well.

 

[serfty]

A new video....Melbourne to Singapore in 4 minutes - YouTube

Good stuff; loved watching the radar after the sun sets. Slicing between storm indications and I presume other aircraft in the area.

 

[jb747]

Just done QF10 overnight and we had a pax who spent a fair while on a oxygen bottle.

It's a rare flight were an oxygen bottle isn't used at some stage. There are plenty on the aircraft, and people who have known medical problems normally make arrangements for them to be available/stowed, etc.

If they would have had to divert it to an airport for a medical emergency it would be very hard to find many airports that you could land an A380 at and then take off as well.

No, there aren't all that many diversion fields available for the 380. But there are enough. Medical problems won't have us diverting into places that might be operationally limiting.

We carry charts and quite a bit of data on any places that we could use, and during the flight keep the FMC updated with routes to some of the alternates, as well as keeping an eye on their weather. Between Singapore and London, there's probably a good alternative available within an hour, and certainly two, for most of the time.

 

[harvyk]

Assuming that they did shut it down (eg some problem forced them to do so) would there really be a significant fuel saving? Wouldn't the extra wear and tear on the plane (considering that the landing gear now has massive amount of sideways forces happening) completely offset any savings?

I have heard internet rumors (the most reliable and accurate place possible) that certain airlines do shutdown engines on taxi to save fuel, however the only plane type that I have heard of this where I could pseudo believe it was Concorde, where they supposedly shut down 2 engines one on each side.

 

[jb747]

Assuming that they did shut it down (eg some problem forced them to do so) would there really be a significant fuel saving? Wouldn't the extra wear and tear on the plane (considering that the landing gear now has massive amount of sideways forces happening) completely offset any savings?

The undercarriage wouldn't even notice the forces. Compared to landing, the sideloads from taxiing around with asymmetric power would be trivial. You can land the Boeings with all of the drift intact at their max crosswind....that would be 15 plus degrees.

I guess savings add up. If an engine is burning around 600 kgs of fuel per hour at idle, that's 10 kgs per minute. If you get to the gate inside the cool down time, there will be no saving at all, but a 10 minute wander around London you could shut down one, and save 50 kgs. If you have 100 aircraft, and they were all able to save that 50 kgs, just once per day, then it would add up to 1.8 million kgs in a year..which is certainly not an amount of money to be sneezed at.

I have heard internet rumors (the most reliable and accurate place possible) that certain airlines do shutdown engines on taxi to save fuel, however the only plane type that I have heard of this where I could pseudo believe it was Concorde, where they supposedly shut down 2 engines one on each side.

Plenty of airlines shut down engines. It's not unusual at all (especially at places where the drive to the runway can exceed the length of the flight (JFK)). But, I'm not convinced that it's done with the big twins (we certainly don't do it with ours, but that doesn't mean others won't come to different conclusions). The quads are a different matter entirely (well some of them anyway).

 

[Harpoon]

Need to ask some of the SQ 777 regulars whether they've noticed it before or if i was dreaming It was a decent taxi in to the gate at changi. I recon we drove from one end of the airport to the other in a big U shape.

 

[Major]

Need to ask some of the SQ 777 regulars whether they've noticed it before or if i was dreaming It was a decent taxi in to the gate at changi. I recon we drove from one end of the airport to the other in a big U shape.

What was your arrival gate ?

 

[NM]

It's a rare flight were an oxygen bottle isn't used at some stage.

But discarding one over the side (or through the side) is not so common ... but does result in a diversion

 

[reductionist]

A new video....Melbourne to Singapore in 4 minutes - YouTube

So good. Thanks JB.

 

[harvyk]

When a flight plan is entered into the FMC, are all waypoints along the way entered in, or are only ones which have a heading change? Also I believe most way points have a 5 letter name? Are there any regions on earth (eg lower south pacific between here and south america) which does not have them? If so how does one fly through those areas? would they simply get the plane to fly to the next waypoint even if it's many thousands of km's away? or would the plane be instructed to fly to certain coordinates.

 

[horseman]

Jb, I have to be among those thanking you for putting so much of your time to our questions. It is always a very interesting read.

 

[Flying Fox]

A new video....Melbourne to Singapore in 4 minutes - YouTube

Thanks. Great video.

So this is what it would look like flying at 72000 KPH

Nice

 

[harvyk]

A new video....Melbourne to Singapore in 4 minutes - YouTube

That was pretty cool, obviously another day at the office for yourself and the other pilots .

A couple of questions, first I noticed the relief pilot was sitting in your seat for part of the flight, how many relief pilots did you have on board for the flight and if only 1 other, did the relief pilot spend some time in the FO's seat as well?

Also you turned the coughpit lighting off a short while prior to landing, is there any hard and fast rules as to when coughpit lighting needs to be switched on and when it's switched off?