Ask The Pilot | Page 760 | Australian Frequent Flyer
Australian Frequent Flyer

Welcome to Australia's leading independent Frequent Flyer and Travel Resource since 1998!
Our site contains tons of information that will improve your travel experience.

Joining AFF is fast, simple & absolutely free - register now and take immediate advantage of these great BENEFITS.

Once registered, this box will disappear. And you will see fewer advertisements :)

Login Now to remove this and all advertisements (GOLD and SILVER members)
Not a member? Register Now for free

Ask The Pilot

Kerrodt

Member
Joined
May 18, 2012
Messages
251
I've also heard from one of the pilots who was on OEJ's flight to the USA. I was curious about exactly how they'd flown the kangaroo.

The FMC has two routes. Primary and secondary. Generally, if you need to make large changes to the route, you'll copy the currently active route to the secondary. Make the change whilst it's in the secondary section, and when happy with it, swap it with the primary route. In this case the flight to the USA was kept separate to the kangaroo, and the position swapped when it was time to fly it. Longer legs were flown in NAV, with the FMC controlling the aircraft to fly the exact track. Most of the turns were done in heading/track mode, with the bank controller being used to get the maximum available bank angle.
Looking at the map of the kangaroo, I imagine that there would have been some very sharp turns and banks to get the angles depicted. Any comments @jb747 on how interesting/exciting that would have been for the crew and what it would have felt like if passengers were on board?
 
Joined
Oct 13, 2013
Messages
10,246
bank controller being used to get the maximum available bank angle
Is this a FBW system. Or some kind of alarm system for pitch roll and yaw? (And thrust?)
What else is FBW on the -400
1)engine throttles ?

what’s required to do a barrel roll in the -400?
 
Last edited:

jb747

Senior Member
Joined
Mar 9, 2010
Messages
9,610
Flights
My Map
Looking at the map of the kangaroo, I imagine that there would have been some very sharp turns and banks to get the angles depicted. Any comments @jb747 on how interesting/exciting that would have been for the crew and what it would have felt like if passengers were on board?
The autopilot, in LNAV mode, uses limited bank angles as the altitude increases. As best I recall, turns at altitude were only about 15º angle of bank in LNAV. But, if you use the heading controller, you could control the actual bank angle in a couple of ways. You could select an actual bank angle (5º, 10º, 15º, 20º, 25º), in which case a turn would be at exactly that angle. Or, you could simply move the turn controller slowly, so that there was never far to turn, which had the effect of keeping the angle small. LNAV ignored any bank angle settings.

At lower levels, such as holding pattern entries, even LNAV would use 30º, with the occasional overshoot to about 35º. When manually flown, 30º was quite normal.

The banks angles used to make the kangaroo were not unusual, and would not have been notable at all to any passengers. So...zero excitement.
 
Last edited:

jb747

Senior Member
Joined
Mar 9, 2010
Messages
9,610
Flights
My Map
Is this a FBW system. Or some kind of alarm system for pitch roll and yaw? (And thrust?)

What else is FBW on the -400
1)engine throttles ?
Only the engines were what we'd recognise as fly by wire.

what’s required to do a barrel roll in the -400?
Ah, the famous Tex Johnson barrel roll.

A barrel roll is a low g manoeuvre. It could probably be done at around 1.5 g. The g is positive (towards the floor) at all times, and varies during the stages of the manoeuvre. I don't recall what sort to g I used in the CT4, when I was doing the low level displays, but I'd expect about 3g.

The 707 (and 747 and A380) are all limited to +2.5g, to -1g. So, in theory all could do it. In practice the FBW limits of the 380 would stop you, but with the system in direct law, it could certainly be done. The simulator was rolled many times....I did so on my last sim exercise.

All of the aircraft had a bank angle warning. This is a quote from the 747 flight manual.
The voice alert BANK ANGLE sounds if bank angle exceeds 35°, 40°, and 45°.
Provides bank angle advisory thresholds at 35°, 40°, and 45° independent of altitude.
An advisory at 35° is provided and another is not given unless 40° is exceeded, and then again only if 45° is exceeded. If the roll rate exceeds the audio callout time, then the bypassed limit is not indicated. Also, when any one of the thresholds is exceeded, the bank angle must reduce below 30° for the process to reset before additional Bank Angle Advisories can be provided.
For example: if greater than 40° is obtained before the 35° callout is complete, another callout is provided only if 45° is obtained or the bank angle is reduced to less than 30° and then again increases to 35°.


The A380's FBW actively stopped you getting beyond 60º, but only in normal law.

 
Last edited:

Saab34

Established Member
Joined
Jul 22, 2008
Messages
1,395
Flights
My Map
So many wear uniform to Sim at all? Or would one be the odd one out.

I guess I would feel more comfortable in uniform, being in the zone etc. That is just me though.
 

flyingfan

Established Member
Joined
Jun 5, 2010
Messages
1,024
Qantas
Platinum 1
Virgin
Platinum
The Flights from Hell thread is full of stories from pax - what about flights from (or to) hell for pilots? QF30 obviously qualifies... any experiences from the pilots?
 

Community Statistics

Threads
86,080
Messages
2,061,937
Members
53,405
Latest member
Poh
Top