Simple question - more of a refresher topic

[blazer05 15]

In the descent and you desire to input a speed in the MCP - so you put in 180 as an example - to have the big ol' girl accept this - you push in the big white button or you "pull" it.

I admit it is a dumb question - and I should RTM - read the manual.  But I am not in front of my flight sim PC.

Thanks and feel free to point out my simplemindedness.

Franklin Duncan (lover of all things PMDG - dying to get the JS41 for P3Dv4.2)

 

[VHOJT 167]

On the 744, you push the button to open the speed window.  You also push it to close it again.

For further info along the lines of your thinking, on an Airbus you would pull the speed button to select your own speed, and you would push it again to let the aircraft manage it.

[berts 97]

On 6/1/2018 at 6:04 PM, VHOJT said:

On the 744, you push the button to open the speed window.  You also push it to close it again.

For further info along the lines of your thinking, on an Airbus you would pull the speed button to select your own speed, and you would push it again to let the aircraft manage it.

Why on earth can't the different aircraft manufacturers standardise on this sort of thing, because it would make life as a newly converting pilot just that little bit easier - and safer?  For example, I will never understand the Airbus logic of having thrust levers that do not move in the correct sense when the power is increased or decreased with the autopilot and autothrottle engaged.

Bertie G 

[Captain Kevin 586]

On 6/1/2018 at 12:56 PM, blazer05 said:

In the descent and you desire to input a speed in the MCP - so you put in 180 as an example - to have the big ol' girl accept this - you push in the big white button or you "pull" it.

Wouldn't you just click on it?

[skelsey 765]

2 hours ago, berts said:

Why on earth can't the different aircraft manufacturers standardise on this sort of thing, because it would make life as a newly converting pilot just that little bit easier - and safer?  For example, I will never understand the Airbus logic of having thrust levers that do not move in the correct sense when the power is increased or decreased with the autopilot and autothrottle engaged.

There is certainly something to be said for standardising; I suppose the issue in a sense is that if you 'standardise' to either the Boeing or Airbus (or CRJ or anything else!) way the argument is that it would then become difficult for pilots experienced on a particular manufacturer's kit to then continue to the new model!

Re: moving thrust levers; there are of course lots of different views on this, but a persuasive one for me is that the levers are just a demand: the only way to actually know what the engines are doing is to verify using the engine instruments, just as with the MCP and FMA. Similarly, thrust levers not moving as expected seemingly did not help the crew of the EK 777 that crashed in Dubai as a result of failing to apply thrust in the go around; in a similar vein, one advantage is that the non-moving nature of the thrust levers means that initiating a go-around etc is a very straightforward and instinctive action of just pushing the thrust levers fully forward to both select the AFDS GA modes and full thrust, as opposed to pressing a small button which may not work under all circumstances!

[berts 97]

Hi Simon,

There may be some merit in what you say, although I haven't researched the EK 777 accident. However, what you say about the thrust levers didn't work for the unfortunate Airbus test pilot either, when he tried to carry out a low go-around at an airshow many years ago and crashed in the woods.  This should have been a relatively straightforward manouevre, so if it is reasonable to assume that he didn't fully understand his aircraft's computerised systems at the time, what chance has the average professional pilot?  At least on a Boeing the Thrust Lever movement always works in a logical sense (just like the gas pedal in a car) whenever the pilots or autothrottle change the thrust required.

I suppose from a piloting point of view the one thing Airbus, Boeing and all of other aircraft manufacturers have in common is that you pull back to go up - and you pull even further back to go down (N.B. not applicable to some hang-gliders and microlights)!

Bertie     

[downscc 1,327]

33 minutes ago, berts said:

I suppose from a piloting point of view the one thing Airbus, Boeing and all of other aircraft manufacturers have in common is that you pull back to go up

I couldn't afford a car when I was learning to fly, my vehicle was a 90cc Honda.  The flight instructor commented during my first hour that I must ride a motorcycle... yup, why?  Because you twist forward to accelerate the bike the you have to pull back the airplane's throttle. I must have been a fast learner 'cause he let me solo after 8 hours.

[berts 97]

Dan, neither could I; but going solo on a 90cc Honda after only 8 hours must be a record!   I wasn't so lucky because I had a 250cc Francis Barnett which I almost gave away to one of my instructors when I learnt to fly.  No, it was not meant to be a bribe, but I cry when I think that the bike is probably worth more now than the aircraft I flew in!

Bertie

[skelsey 765]

Hi Bertie,

1 hour ago, berts said:

However, what you say about the thrust levers didn't work for the unfortunate Airbus test pilot either, when he tried to carry out a low go-around at an airshow many years ago and crashed in the woods.  This should have been a relatively straightforward manouevre, so if it is reasonable to assume that he didn't fully understand his aircraft's computerised systems at the time, what chance has the average professional pilot? 

I assume you are referring to the Habsheim crash? In this instance, although much has been made of the (possible) contribution of the FBW systems, the data from the investigation would seem to support the conclusion that this essentially an energy (or lack of) issue.

The aircraft was flown at 30 ft RA (disputed by the Captain, but supported by all the available DFDR and CVR data), at a speed of 122 knots, 15 degrees nose up with the engines at flight idle -- hardly an ideal situation to start a go around from! When the approaching treeline was observed, the thrust levers were selected to TOGA -- but as you will appreciate, engine response from idle in any large turbofan is far from instant. In this particular case, it took about four seconds to spool up from flight idle to 67% N1, and a further second to reach 83% N1; entirely within the expected engine performance. Meanwhile, of course, the aircraft continued effectively on the stick shaker -- the FBW computers intervening to maintain maximum AoA and prevent a stall -- but of course without either thrust (due to the engines spooling up) or excess airspeed any climb was simply beyond the laws of physics.

The Captain subsequently claimed a number of things, including that he wasn't that low, that he increased thrust earlier than the data sugested and that the FBW prevented him from raising the nose any further and therefore compromised his ability to climb away. I don't know about you, but it seems extraordinary to me on an otherwise serviceable aircraft simultaneous faults could suddenly arise with the radio altimeter, thrust levers, FBW system, DFDR and GPWS particularly when the videotape of the incident from the ground very much supports the investigation's conclusion that this was less to do with technology and more to do with flying low, slow, nose-high and with (effectively) nil thrust on...

1 hour ago, berts said:

I suppose from a piloting point of view the one thing Airbus, Boeing and all of other aircraft manufacturers have in common is that you pull back to go up - and you pull even further back to go down (N.B. not applicable to some hang-gliders and microlights)!

Very true!

[VHOJT 167]

3 hours ago, skelsey said:

Hi Bertie,

I assume you are referring to the Habsheim crash? In this instance, although much has been made of the (possible) contribution of the FBW systems, the data from the investigation would seem to support the conclusion that this essentially an energy (or lack of) issue.

The aircraft was flown at 30 ft RA (disputed by the Captain, but supported by all the available DFDR and CVR data), at a speed of 122 knots, 15 degrees nose up with the engines at flight idle -- hardly an ideal situation to start a go around from! When the approaching treeline was observed, the thrust levers were selected to TOGA -- but as you will appreciate, engine response from idle in any large turbofan is far from instant. In this particular case, it took about four seconds to spool up from flight idle to 67% N1, and a further second to reach 83% N1; entirely within the expected engine performance. Meanwhile, of course, the aircraft continued effectively on the stick shaker -- the FBW computers intervening to maintain maximum AoA and prevent a stall -- but of course without either thrust (due to the engines spooling up) or excess airspeed any climb was simply beyond the laws of physics.

The Captain subsequently claimed a number of things, including that he wasn't that low, that he increased thrust earlier than the data sugested and that the FBW prevented him from raising the nose any further and therefore compromised his ability to climb away. I don't know about you, but it seems extraordinary to me on an otherwise serviceable aircraft simultaneous faults could suddenly arise with the radio altimeter, thrust levers, FBW system, DFDR and GPWS particularly when the videotape of the incident from the ground very much supports the investigation's conclusion that this was less to do with technology and more to do with flying low, slow, nose-high and with (effectively) nil thrust on...

Very true!

What I'm interested in is what the procedure is to disable the autothrottles that they went through (if I'm remembering right?)

The other thing I've always wondered about Airbus is it does have moving trim wheels so you can see what the trim is up to - I wonder why that moves and they decided that throttles don't?

Edited June 4, 2018 by VHOJT

[Ephedrin 418]

2 hours ago, VHOJT said:

What I'm interested in is what the procedure is to disable the autothrottles that they went through (if I'm remembering right?)

Simon (or Kyle) might knock me out now... But If I'm not completely wrong you don't actually disable them anyway for a go around. Simple move the levers (as they are actually no throttles) from Climb detent fully forward to TO/GA and the FADEC will do the rest for you... that's the sense about the airbus system... You never really fly the aircraft unless you're in direct law (and even then not like a Boeing) but ask the airplane and the Flight Augmentation Computers to do something for you to get to a certain point. 

Even when your doing a fully "manual" landing (Thrust levers manually between CLB and IDLE detent) you don't run the engines manually but ask the FADEC to bring the engines to a thrust setting to de/accelerate that ot that fast.

[Ephedrin 418]

3 hours ago, VHOJT said:

The other thing I've always wondered about Airbus is it does have moving trim wheels

afaik backup cable connections for the stabilizer on eariler Airbuses

[berts 97]

On 6/4/2018 at 12:46 AM, skelsey said:

Hi Bertie,

...........it seems extraordinary to me on an otherwise serviceable aircraft simultaneous faults could suddenly arise with the radio altimeter, thrust levers, FBW system, DFDR and GPWS particularly when the videotape of the incident from the ground very much supports the investigation's conclusion that this was less to do with technology and more to do with flying low, slow, nose-high and with (effectively) nil thrust on...

It is also alleged that a local airline changed their boarding music to Teddy Bear's Picnic and the Forestry Department ordered six.