Speedbrake Arming

[Bluestar]

I watched this video by Captain Obet on the arming of the speedbrake using the reverse thrusters.  When I move the reverse thrusters the speedbrake does not ARM at first.  As I continue to move the reverse thrusters the speedbrake handle will move and the speedbrakes are deployed. Is this something that I need to adjust on my system? 

https://www.youtube.com/watch?v=7-Slnntm1QE

[John H Watson]

Looking at videos I took myself with the engine not running and the Speedbrake Auto circuit breaker pulled (real aircraft), the speedbrake lever begins to move from the down position at about 1 to 1.5 reverser knob thicknesses (in the vertical plane). By the time the reverse levers have reached their first "clickstop"/detent, the speedbrake lever is fully lifted. The linkage is a mechanical system linked to the #2 and #4 levers.

Moving the reverser levers will not move the speedbrake to the ARM position marked on the speedbrake quadrant (where there is a microswitch), but will activate a different microswitch in the thrust quadrant when the lever has come out of its groove. 

What are you seeing in PSX?

[Hardy Heinlin]

I watched this video by Captain Obet on the arming of the speedbrake using the reverse thrusters.  When I move the reverse thrusters the speedbrake does not ARM at first.

Yes, it does. Zoom in and look very closely :-)

Load this situ:

Basic 002 - On ground and doors closing.situ

The "M" in the "ARM" word is hidden and the lever part under the speedbrake knob is dark (in the hole).
When you lift the reverse lever #2 or #4 in PSX, the lower half of the "M" becomes visible and the part under the knob gets brighter (out of the hole).


When you do the same action in a later preflight phase, e.g. ...

Basic 003 - On ground and cleared for engine start.situ

... the speedbrake will start to autorun to UP only when the ARM position is reached -- not earlier.

It's all correct. You need not adjust anything. Just zoom in to see it :-)


Regards,

|-|ardy

[Bluestar]

Hardy,

Thanks for clarification.  I figured I might be missing something, just didn't know where to look.

[John H Watson]

... the speedbrake will start to autorun to UP only when the ARM position is reached -- not earlier.

It's all correct.

On the real aircraft, the lever only moves up vertically out of the detent with the use of the reversers. It doesn't move aft to the ARM decal position. Using the reversers triggers an out-of-detent microswitch "S861", not the ARM position microswitch "S217". Hardy: See Elec/Instr Book 7.

https://youtu.be/9kg37qo4ohc

The speedbrake actuator should run at or even slightly before the lever reaches its highest point (out of the detent). The adjustment of the switch is based on speedbrake lever "height" rather than reverser lever angle.

[Hardy Heinlin]

My forum comment was simplified. In PSX, in fact, the lever just raises off the detent hole like on the real aircraft. It doesn't exactly reach the ARM line. That's why you need to zoom in to see the raising effect. When you release the reverser lever, the speedbrake lever will fall back into the hole like on the real aircraft. That wouldn't be possible if it were to go to ARM.

[Bluestar]

I ran the Sydney-Los Angles.situ in an attempt to get the speedbrake to arm by pulling the thrust reversers back.  On my system the the speedbrake never armed as I pulled the thrust reversers back prior to reaching the first detent.    Once reaching the first detent the speedbrake moved to the UP position and never did show ARMED.   

It appeared to me from watching the video that the speedbrake lever started moving up as soon as the reverse thrust levers started moving toward the first dent and were armed in the first detent.   

[G-CIVA]

When I deploy my reversers the speedbrake lever does appear to move correctly inside the PSX simulation just like the YT video.

[John H Watson]

Once reaching the first detent the speedbrake moved to the UP position and never did show ARMED.   

What do you mean by "show ARMED"?

In the first youtube video, the hydraulics are probably not switched on, so the speedbrake lever doesn't move backwards, just upwards.

[Avi]

Bode,

Captain Obet is wrong and misleading here (and not for the first time).

When he says "armed", it is not armed at all.

The speedbrake lever is ARMed when the pilot takes it out its groove and move it slightly backward (so it won't gate into the groove again). In this case you will get a memo message (always in PSX and it is an airline specific in the real world).
The lever is moved by an actuator. There are many conditions before the actuator gets power to move the lever to UP position. One of the conditions is lever ARMed. The reason is that if the lever is not ARMed (it is not outside the groove), the actuator will try to move the lever to the UP position with no way to succeed (it can burn out) so it doesn't get power.

If the lever is not ARMed, there is a "bypass" condition. When you select reverse thrust on #2 or #4, a mechanical links pulls the lever out of its groove. In this case the actuator will be able to move the lever to UP so it gets power but this situation is NOT considered as lever ARMed. Captain Obet is wrong here. It is a way to move the lever to UP without arming it (if the pilots forget to do it).

Hope it makes sense to you.

Cheers,

[Bluestar]

What do you mean by "show ARMED"?

In the first youtube video, the hydraulics are probably not switched on, so the speedbrake lever doesn't move backwards, just upwards.

If the cursor is placed over the speedbrake handle the cursor will show a blue SPD BR. By moving the speedbrake handle slowly down (toward UP) with the mouse, the cursor will change from a blue SPD BR to an orange ARMED. 

[Bluestar]

Bode,

When he says "armed", it is not armed at all.

Avi,

So what you are saying is the speedbrake lever is moved out of the "groove" when the reverse thrust is selected and out of the "groove" in this situation is not ARMED.

Thanks for the clarification.

[Avi]

Right

[John H Watson]

f the cursor is placed over the speedbrake handle the cursor will show a blue SPD BR. By moving the speedbrake handle slowly down (toward UP) with the mouse, the cursor will change from a blue SPD BR to an orange ARMED. 

PSX labelling reflects the activation of the "armed" microswitch (about 3 degrees, according to the Boeing Maintenance Manual, from the fully forward position), rather than the activation of the "out of the groove" microswitch. 

Like Avi, I've noticed a few "errors" Captain Obet's explanations, but Captain Obet has explained to me that he simplifies his terminology for the average YouTube viewer.

I'm trying to remember what generates the EICAS message SPEEDBRAKE ARMED. I've looked through all the Boeing manuals and there is no clear link between the various speedbrake handle position sensors and microswitches and the EICAS. The speedbrake handle even has an input into the autopilot computers. Perhaps the EICAS gets SPEEDBRAKE ARMED info from the A/P computers?

[nimsu87]

I was just on here as I had a similar question although not from Obet's video, although I am familiar with his videos; for somebody to call him 'wrong' though is quite stupid since he actually, y'know, flies the real heavy metal version of the 747-400 and -800, and instructs other pilots too. Perhaps one should note the caveat the majority of pilots state at the beginning of their vlogs 'edited for entertainment purposes, should not be used for instruction'. To call him misleading and finishing with (not for the first time) is also uncalled for. His videos aren't training material, they're a courtesy from as pilot who just wants to give a bit of insight into his job as a pilot. I read a lot on here and comment very little. calling a 747-4/8 pilot wrong, it almost makes me laugh, but saying he is misleading people is slander, I don't know how you got away with writing that here to be honest.

[John H Watson]

I was just on here as I had a similar question although not from Obet's video, although I am familiar with his videos; for somebody to call him 'wrong' though is quite stupid since he actually, y'know, flies the real heavy metal version of the 747-400 and -800, and instructs other pilots too.

We are not accusing Obet of being deliberately misleading. However, some of Obet's videos are done in the presence of other pilots. Some sound instructional for the pilots' sakes, but the language is still at YouTuber level and not as clear as one would have expected. i.e. open to different interpretations.

You can't elevate any human to god status. Are you saying a check captain was never wrong or never crashed an aircraft? If Boeing aircraft manuals can be wrong, so can pilots and engineers. You see this all the time on this site because the sim goes into so much detail.

There are proper training videos for 747 pilots on YouTube which escaped Boeing/airline classrooms, which are plainly wrong in some areas.

There is another YouTuber 747 pilot who gets corrected continually in the comments section when he goes beyond his technical expertise. 

[cavaricooper]

I would offer that some of this group are more intimately familiar with the intricacies of 747-400 than many line pilots.

I learn here daily.

C

[nimsu87]

I am not worshipping anybody, the issue I have is when the word 'misleading' is used, and no of course I don't think a check captain is perfect, you've missed the point. My comment also wasn't directed at you as your opinion of Obet was a lot more balanced. But a person on here with no listed specialist knowledge having a dig at a pilot who he obviously has a problem with; (e.g) saying that Obet is wrong and calls him misleading; whilst hiding behind a keyboard and not sharing his credentials is what annoys me. I agree that many users of this forum probably do know more about the deep systems on the 744 thanks to Hardy. However, the majority will not have flown either the 744 or 748 like Obet has.

[Hardy Heinlin]

Nimsu87, for many of us, English is not our native language. Misunderstandings may occur, especially when expressing things where readers may confuse technical phrases with personal or emotional phrases. Regarding Avi: He's been using PS1/PSX for about 25 years, has developped some add-ons (the CMC simulation is probably his best one), and has privately studied tons of maintenance documents. He (along with J.H.Watson) was on the PSX-Alpha-Test team from day 1 on (started in 2008) and discovered a zillion mistakes I made during the first six years of my PSX development. Thanks to Avi, PSX became a better sim. I need such guys as I am a perfectionist :-)


Regards,

|-|ardy

[nimsu87]

Thanks for clearing that up Hardy, I'm not just saying that because this is 'your' forum but I think that when you mentioned that not everybody speaks English as a first language and the fact that even misunderstandings can occur between two native speakers, when messages are sent via text especially. Apologies to you Avi, thanks for helping PSX be the sim it is today. I would also apologise even if you weren't in Hardy's team. I saw that you're from Israel and without sounding patronising, because I don't intend it, we don't speak our respective languages natively! I for one as your stereotypical Englishman isn't even bilingual! All the best. Appreciate your input Hardy, I had my head stuck up my ar__. Which is too easy to do when using forums I think!