"THROTLLE HOLD" OR "THRUST HOLD" On B-767-300

[Fpetrowitsch]

Hi everybody, I¨m locking for some information about B-767-300. On the take-off run and after the 80 kts. check, the correct call out after FMA indication of THR HOLD is, THROTLLE HOLD Or THRUST HOLD. If somebody knows about this, from where did you get the info? Thankyou very much.

[Intruder]

It's whatever your FCOM says, since it's not standard among airlines. We have "Thrust set."

[AllInstructedOut]

Thrust Hold is more applicable flying a jet. Our airline has no call apart from Thrust Set. I have never heard of Throttle Hold.

[Mach E Avelli]

Strictly speaking, the levers are not throttles anyway, though the term lingers on in some old Boeing books. Throttles are usually associated with piston engines. 'Thrust levers' is the more technically-correct term for those thingies that you push forward to go faster.
Most operators use the simple call-out "thrust set" as confirmation that a) the FMA caption says whatever it is supposed to and b) the N1, EPR (or whatever parameter is applicable to the type) is where it should be. The danger with terms like 'throttle hold' is that the pilot will fixate on the caption displayed to the exclusion of other indicators which are more critical.

[ironbutt57]

I agree there are no "throttles" per say in a jet engine, Boeing refers to "auto throttle", and Throttle hold mode is when the mechanical clutches are disengaged allowing the thrust levers to be moved by the pilot, even though the auto throttle system is active...no specific thrust setting is "held/maintained" the authrottle clutches are simply in a "null mode"

"Throttle hold" is the proper nomenclature...

[Spooky 2]

Since Boeing does not specify any call out for this mode I wonder why there is anything other than a just plain "HOLD" as annunciated on the FMA. That is after all what you are verbally acknowledging, right? Sometimes less works best.

[Mir]

Not flying the 767, but on the 737, so can't say, if it's the same, but there is a reference in our FCOM under the abbreviations section for THR HOLD as being Throttle Hold.

[The Dominican]

Throttle hold, is the correct term in the Boeing manuals regardless if it is the correct technical term or not. At take off, in my company is a silent verification (the only case, all other phases of flight is the call "throttle hold") so it really all depends on you company's SOP's.

[Spooky 2]

Don't want to beat a dead horse here in this conversation but in Boeing speak the term is "Thrust Levers" and the Auto Throttle operates the the thrust levers as required.

Your manual may have something different because it has been tailored to your company operating philosophy and that is what you want to use in your operations. Many operators have used the verbals that sound like this "80 knots, Hold." No problem so if that is in your SOPS, simply comply and everyone will be happy.

Boeing's master FCOM, FCTM and QRH do not use the terms throttle hold. Nor do they show any call-out that uses the terms, Throttle Hold, Hold, etc., just 80 kts from the PM and Check form the PF. Your company may have something different...use it accordingly

[ironbutt57]

It's because the autothrottle system is in "hold" mode...

[Mach E Avelli]

But wotif the auto-throttle is unserviceable or trips out just before 80 knots? Not reason enough to reject the takeoff, unless thrust itself doesn't meet the target. Hence, many operators prefer the 'thrust set' call.
But, as has been stated elsewhere, whatever your Company SOP has written down in the Good Book (FCOM) is what you should say/do regardless of the logic.

[WaynerMenard]

Thrust Hold is more applicable flying a jet.

[ironbutt57]

We called "thrust set" at 80 its to assure the correct thrust was set thus enabling us to meet the performance requirements, then the AUTOTHROTTLE SYSTEM goes into the "throttle hold" mode, which leaves the autothrottle clutches disengaged to allow further lever movement without interference from the system...

"Throttle hold" has nothing to do with any particular thrust setting, it simply puts the system in a "standby mode" so to speak during the takeoff, and other phases of flight to allow free movement of the thrust levers, without completely de-activating the auto throttle system...simple really..

[The Dominican]

We called "thrust set" at 80 its to assure the correct thrust was set thus enabling us to meet the performance requirements, then the AUTOTHROTTLE SYSTEM goes into the "throttle hold" mode, which leaves the autothrottle clutches disengaged to allow further lever movement without interference from the system...

"Throttle hold" has nothing to do with any particular thrust setting, it simply puts the system in a "standby mode" so to speak during the takeoff, and other phases of flight to allow free movement of the thrust levers, without completely de-activating the auto throttle system...simple really..

Exactly! But apparently it is not that simple :rolleyes: The FMA announces the mode, it has nothing to do with mechanical levers, and the mode is "Throttle Hold"

[3holelover]

Trusting that the OP has his answer by now, I thought I'd offer some alternate nomenclature for the Thrust Levers that I've heard over the years:

Go sticks
BFK's (Big F___ Knobs)
Back Slap Adjusters
Noise Selectors
Volume Knobs
Loud Makers
Sizzle Sticks
Singer Sticks
Gas Givers
Punch Pickers
Power Poles
Grunt Givers

Any more I might have missed?

[captplaystation]

Go faster levers

[Jetjock330]

B777-300ER,
"Thrust Set" is called before 80 kts, Pilot monitoring calls "80 kts" and pilot flying calls out the FMA thrust change to "HOLD" which happens at 80 kts. The auto-throttle has memorized the thrust setting and maintains that thrust regardless of an auto throttle failure. This is our Company way.

[ironbutt57]

The throttle hold mode is there to allow adjustment of the thrust levers, the clutches are disengaged, the autothrottle system is still active, same as when one performs a cruise descent, the auto throttle system sets a thrust setting that equates to approximately 1200fpm, then once again we see throttle hold mode...when alt cap occurs the autothrottle system will re-enter the speed mode...

[ImbracableCrunk]

Are you sure about that? Throttle Hold is there not to allow you to make adjustments, but to prevent an A/T fault from making an adjustment.

[South Prince]

Go Sticks - Noise selectors.

My favourite.

[ironbutt57]

Are you sure about that?

Try it....it allows for manual adjustment of the thrust levers without deactivation of the autothrottle system

[ImbracableCrunk]

The ability to move the TLs in THR HLD is a byproduct and it rates a "*Note", not the reason.

[Pub User]

It also allows the pilot to manually increase thrust on a working engine in the event of failure of the other. Not essential, of course, but often both desirable and permitted.

[barit1]

McD and Airbus persisted in calling them "throttles" (holdover from piston jargon), while Boeing started the more generic "thrust lever" jargon. Why they didn't call 'em "speeder spring lever" is anybody's guess, but in the day of hydromechanical controls, that's exactly what they did. Ham Standard, Bendix, Woodward, and I'm sure many others used flyweight governors to control rotor speed and thus thrust.

[ironbutt57]

Everyone now calls them thrust levers, the "throttle Hold" comes from the auto-throttle system mode, hydromechanical-based engines do have a throttle of sorts, the manual fuel valve...if it's a by-product, then its a good one, try retarding the thrust levers before 80kts without disconnecting the autothrottle system and see what happens, the Throttle hold mode is there specifically on take-off, and other phases of flight to allow precisely that, or during a FLCH descent to allow the pilot to increase the thrust as desired to lessen the rate of descent, while at the same time the auto throttle system remains available to revert to speed mode when level-off is achieved...

Now....what your airline's callout when the FMA displays this mode may vary, the actual mode is "throttle hold" as this is precisely what has happened, the clutches have been de-energized to allow manual adjustment if desired, but the auto throttle system remains active to revert to the appropriate mode when needed, (climb after take-off, speed, when level off happens after a descent)

[Brian Abraham]

Throttle or thrust. Military (US) calls it a throttle in their jets. Even those built by Boeing. :8
Should add that's fighters.

[ironbutt57]

Boeing calls them "thrust levers" that are commanded by an "autoTHROTTLE" system...or the pilot in case of the Autothrottle system being switched off...or active, but in the "throttle-hold" mode as annunciated on the FMA...

[Jetjock330]

A copy and paste from Boeing 777 FCOM in 2 parts:

In flight:
Push (after lift-off with takeoff reference thrust limit displayed) – • removes takeoff and climb derates and assumed temperature thrust reduction • A/T in HOLD, activates A/T in THR REF mode • disarms LNAV and VNA V, if armed • between 50 feet and 400 feet, selects TO/GA roll mode • above 400 feet, selects TO/GA roll and pitch modes

*Annunciations are: • THR – autothrottle applies thrust to maintain the climb/descent rate required by the pitch mode • THR REF – thrust set to the reference thrust limit displayed on EICAS • IDLE – displays while the autothrottle moves thrust levers to idle; IDLE mode is followed by HOLD mode • HOLD – thrust lever autothrottle servos are inhibited. The pilot can set thrust levers manually*


I hope this helps somewhat! Will find the link with respect to take-off!

[ironbutt57]

Bit different with FADEC engines...as opposed to non-fadec on some 75/767's

[Jetjock330]

Found more, copy and paste of FCTM B777-300ER:

The PM should verify that takeoff thrust has been set and the throttle hold mode (HOLD) is engaged. Once HOLD annunciates, the autothrottle cannot change thrust lever position, but thrust levers can be positioned manually. The HOLD mode remains engaged until VNAV engagement or another thrust mode is selected.
Note: Takeoff into headwind of 20 knots or greater may result in HOLD before the autothrottle can make final thrust adjustments.

The HOLD mode protects against thrust lever movement if a system fault occurs. Lack of the HOLD annunciation means the protective feature may not be active. If HOLD annunciation does not appear, no crew action is required unless a subsequent system fault causes unwanted thrust lever movement. As with any autothrottle malfunction, the autothrottle should then be disconnected and desired thrust set manually.