Ask The Pilot

[Fruitcake]

have you ever requested the CSM move passengers forward to help adjust the trim...

"If there are any electricians on board, please make yourself known to the crew, my trim button has broken." ?

 

[ChrisGibbs]

One for the regional turbo prop drivers on this thread. I was onboard today's QF41 SYD-CGK service. As we commenced our taxi from the international down to the southern end of the field for a take off on 34L I noticed a QF Dash 8 across the other side of 34L taxiing towards the domestic terminal with its left hand engine shutdown. I've seen this over the years with some European airlines that sometimes taxi to and from the runway on one engine (e.g. Olympic Airways) but hadn't seen it previously with the QF domestic fleet. Assuming there was nothing out of the ordinary with this one does taxing on one engine create any assymetric challenges? I would imagine attempting the right hand turn into the domestic apron with power only on the right hand engine would create some challenges.

Thanks in advance.

 

[jb747]

have you ever requested the CSM move passengers forward to help adjust the trim or CG toward the latter stages of the flight or just before commencing landing configuration?

If I had to move anyone for trim reasons...it wouldn't be a request.

But, to answer your question. No.

When the aircraft is loaded, it isn't done so randomly, with the resulting trim just accepted. There are trim targets that must be met. Basically, the trim has to be within the manufacturer's allowed range, for take off, all stages of the cruise, and landing, and the initial loading has to accommodate this, and cater for the fuel burnt during the flight.

 

[jb747]

"If there are any electricians on board, please make yourself known to the crew, my trim button has broken." ?

What trim button would that be?

 

[jb747]

One for the regional turbo prop drivers on this thread. I was onboard today's QF41 SYD-CGK service. As we commenced our taxi from the international down to the southern end of the field for a take off on 34L I noticed a QF Dash 8 across the other side of 34L taxiing towards the domestic terminal with its left hand engine shutdown. I've seen this over the years with some European airlines that sometimes taxi to and from the runway on one engine (e.g. Olympic Airways) but hadn't seen it previously with the QF domestic fleet. Assuming there was nothing out of the ordinary with this one does taxing on one engine create any assymetric challenges? I would imagine attempting the right hand turn into the domestic apron with power only on the right hand engine would create some challenges.

It's not as big and issue as you might imagine, as long as you have all of the appropriate hydraulic services.

Even though it's not as obvious, it is also happening (sometimes) with the jet aircraft after landing. The coughulative saving in fuel use is huge.

 

[meloz]

No.







I think there's a lot of mythology about that incident.

Care to elaborate?

 

[RooFlyer]

If I had to move anyone for trim reasons...it wouldn't be a request.

But, to answer your question. No.

When the aircraft is loaded, it isn't done so randomly, with the resulting trim just accepted. There are trim targets that must be met. Basically, the trim has to be within the manufacturer's allowed range, for take off, all stages of the cruise, and landing, and the initial loading has to accommodate this, and cater for the fuel burnt during the flight.

After the eruption of Mt St Helens, I was on a flight Seattle to Las Vegas (IIRC) and the coughpit announced that the volcano could be seen off one side. I swear that the entire other side pax stood as one and moved as far to the other side as they could ( in reality a bunch of people got to the aisles).

I foresaw us plummeting sideways, but barely a ripple. Phew.

 

[jb747]

Care to elaborate?

Racist/anti arab tales.

The aircraft was still in the hands of the maker. One of their engineers was in charge of the whole affair.

 

[jb747]

After the eruption of Mt St Helens, I was on a flight Seattle to Las Vegas (IIRC) and the coughpit announced that the volcano could be seen off one side. I swear that the entire other side pax stood as one and moved as far to the other side as they could ( in reality a bunch of people got to the aisles).

I foresaw us plummeting sideways, but barely a ripple. Phew.

Moment arm.... If every passenger in an A380 walked to one side, you'd have about an additional 25 tonnes of people on that side. The fuselage is about 7.5 metres wide, so they'd be an average of about 1.8 metres from the centre. So, 25 tonnes*1.8m....

The aircraft is quite capable of handling the roll moment caused by a fuel tank leak, so you could be looking at around that same weight of 25 tonnes, but this time about 25 metres from the centre, so generating a roll moment about 13 times greater. Upshot is that lateral passenger movement would be barely noticeable.

 

[meloz]

Racist/anti arab tales.

The aircraft was still in the hands of the maker. One of their engineers was in charge of the whole affair.

That was my understanding of the incident as apposed to the childish racist emails that did the rounds.

Meloz

 

[Fruitcake]

What trim button would that be?

Good point. I've flown QF's sim so I know the 747 has a rocker switch on the yoke for elevator trim, but does a fly by wire aircraft even need a manual trim input of some kind?

 

[jb747]

Good point. I've flown QF's sim so I know the 747 has a rocker switch on the yoke for elevator trim, but does a fly by wire aircraft even need a manual trim input of some kind?

It gives access to pitch trim in direct law only. In the other laws trimming is automatic. So, there's no button on the sidestick. There is rudder trim on the pedestal, and it's only used for the engine out case. The pitch trim switch is just in front of the rudder trim on the pedestal, and only functions after the direct law reversion. The aircraft provide no access to roll trim.

 

[Fruitcake]

In the other laws trimming is automatic.

Suddenly, fly by wire via side stick controller with no artificial feel makes an awful lot of sense. For some reason I'd never thought of it this way before.

 

[williamsf1]

I found this interesting clip from KLM showing how a flight between AMS and JFK . It shows how they programme the auto pilot and track https://www.youtube.com/watch?annot...&feature=iv&src_vid=9NFq2eZSDJE&v=fwqEe0XkggI

Another is KLM 747 AMS to St Maarten https://www.youtube.com/watch?v=7GZ3fSDFevE&spfreload=1 showing how they prepare and land on such a tricky runway

**mods please feel free to move to another thread

 

[jb747]

Put it into context. The runway is about the same length as 07/25 in Sydney, or 27/09 in Melbourne. Many of the approaches shown in videos (and this is not one) are actually stupidly low at the threshold, and are obviously aimed short...not for any aviation reason.

 

[Mattg]

Hi jb747,

I was flying on an Embraer 170 the other day and it was announced before boarding that the lavatory on board the aircraft was unserviceable, but only below 1,800 feet. Any idea why this might be the case?

 

[jb747]

I was flying on an Embraer 170 the other day and it was announced before boarding that the lavatory on board the aircraft was unserviceable, but only below 1,800 feet. Any idea why this might be the case?

I don't specifically know how the E170 toilet system works, but I expect that it's a bit better than a VicRail hole in the floor. I'd expect that its using bleed air to pressurise the system, so above that level the system is probably out of its take off phase and pressurising the aircraft. Toilets aren't something I take much note of, as long as they work....

 

[mjt57]

JB, given the probable finite future of QF's 744 fleet, will Those Who Make the Big Decisions look at using the 380s to fly into JFK?

Given your views on this matter and what I saw when there recently (a number of 380s parked out in the middle of nowhere), I'm wondering if QF will continue this service.

We're looking at more regular trips to NY over the next few years, and I'd like to stick to one airline, if possible, aside from brand loyalty, to accumulate points, etc..

 

[juddles]

Hi jb747,

I was flying on an Embraer 170 the other day and it was announced before boarding that the lavatory on board the aircraft was unserviceable, but only below 1,800 feet. Any idea why this might be the case?

Probably unwise to be in the toilet at that level anyway!!

What Happens When You Flush a Toilet on an Airplane?

just for a laugh...

 

[jb747]

JB, given the probable finite future of QF's 744 fleet, will Those Who Make the Big Decisions look at using the 380s to fly into JFK?

Given your views on this matter and what I saw when there recently (a number of 380s parked out in the middle of nowhere), I'm wondering if QF will continue this service.

We're looking at more regular trips to NY over the next few years, and I'd like to stick to one airline, if possible, aside from brand loyalty, to accumulate points, etc..

It's really a QF question, which I'm sure could find a home on another thread. I have no idea what they plan.