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757/767 Differences

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757/767 Differences

Old 16th Nov 2007, 07:59
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The 767 does not have a PTU !
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Old 16th Nov 2007, 08:41
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No PTU but it does have a Pitch Enhancement System (PES).
"Heavy Hydraulic System" Left on 75, Centre on 76.
75 all hyd pumps function all the time, 76 has an element of demand in the secondary pumps.
75 C Hyd is 2 electric, 76 Primary is Air Driven Pump (ADP), secondary 2 electric.
CF6 80A reversers are hydraulic, CF6 80C reversers are pneumatic
To be anal, it is the Bleed rather than Aircon that has different valve configs. 75 has one,on 76 one for eaxh L and R Eng Bleed with a Centre (or Body Duct) isolation as well.
Discrete lights different on Bleed system of 76 and mean different things (Also varies with -200 and -300 dependant on engine fitted) Let's put that in the "Too difficult" file!
75 single aisle, 76 twin.
75 2 zones for aircon in cabin 763, 3 zones
Additional Trim Air Valve position indicator for Flight Deck on 763
Autoland: Things happen at different heights on the 76 (such as nose up trim bias etc) See "Too difficult" file.
76 cargo hold fitted for ULD, 75 is bulk loading
Cargo heat on 76, not on 75
Waste tanks from crappers at rear and single drain, vacuum type on 76, caravan type chemical and multiple drain on 75
Crew oxygen overpressure blow off indicator in different places
Forward cargo hold lock indicators fitted on 763, not on 75.
Electrics arranged slightl;y differently (See "Much, much, much too difficult" file.
Sold as a common type but built in different plants and the design teams did arrange to have lunch together once but it never happened.
Can't think of any more. I'm off to polish my lawn mower.
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Old 16th Nov 2007, 09:39
  #23 (permalink)  
 
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yeoman, are you sure about the B767 C hyd system? On my brand of B767 the C hyd system has 2 electric primary pumps and an air demand pump.
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Old 16th Nov 2007, 11:21
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Ok maybe i'm getting the wrong end of the stick here.
We are talking about the main passenger doors L1, (and possibly L2) being electrically operated by the crew to open and close them from the inside?
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Old 16th Nov 2007, 12:17
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Mustafa

You are quite correct, mea culpa etc! Next time you are in the sim (if you haven't already tried this!) look at an ADP failure on Take Off. It gets quite exciting. The ADP fails and as it is the big mama of pumps in the C system (37 odd gpm as opposed to 5 gpm for each electric IIRC) the gear takes several days to retract. This means that you get a Gear Disagree as it over runs the time inhibit. You also get a SYS PRESS message as the pump has been signalled to operate so that inhibit is also removed. There will also be a PRESS discrete on the pump pnael. As the situation lasts over however long, you also get a latched MAINT message on the Status page.

Once the gear comes up it all goes away like magic. Gives you hours of fun if you are running the exercise, not so much fun if you are in the seat as it all happens seconds after take off.

Another good one is to fail an ADC on take off but that is for another day!"

Doors: Electric at L1 and L2, up and over, operable from inside and out. (L1 only on -200). That's the TOM fit, don't know if it is an option or not.
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Old 16th Nov 2007, 14:15
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Silverjet 762's

Not really my area for tech purposes, but I can confirm all of Silverjets 767's L1 doors are electrically operated. You need to manually rotate the handle to release the door and you will find a button on the L1 Panel that says 'Door Up'...
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Old 16th Nov 2007, 15:49
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G-SILC does not have electrically operated doors. You have to lift the handle (inside and outside), the loaded spring pulls the door up partially and you have to manually lift the door the rest of the way. I was intimate with the door for the duration of the check when it was in our hangar. In order to remove the forward toilet I had to remove the trim and the interior handle on the L1 door.

And yes I was refering to the Canadian reg Zoom's, also specifically C-GZUM which was the first 767 that I had to rig the door handle (the old 4-5 inch block of wood under the exterior handle as per the AMM).

This is like beating my head on a rock so I am going back to lurking.


pAnmAn
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Old 16th Nov 2007, 22:45
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Well...heck, as long as everyone else has an opinion on the electric doors let me just say that the Quantas B767-238ER has a electric door at 1L and all others are manual.
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Old 17th Nov 2007, 01:35
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767 still in production

757 Gooone
(and ugly)

S_cct
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Old 17th Nov 2007, 02:16
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Ugly?

Hrrumppph. That's a matter of opinon. I think it's the sexiest looking airliner.

Long legs, slender build, with nice, powerful jugs. What's not to like?
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Old 17th Nov 2007, 06:20
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The 767 does not have a PTU !
Many but not all of the 767-300 in the QF fleet have a PTU.
Lives in the stab compartment... Drives the stab when sh$ts are trumps..
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Old 17th Nov 2007, 07:11
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Couldn't agree more, Misd'

One powerful,powerful lady!

Flown a few empty on positioning flights post maintenance WOW! - 40odd tonnes of thrust lifting 50odd tonnes of empty aircraft- YYAAAHHHOOOOO!!!!

Like sha**ing a fat bird!- Bloody good fun at the time, leaves you covered in sweat but you don't want to do it ALL the time!
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Old 17th Nov 2007, 08:04
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Think you will find the monarch 767 has electrically assisted l1 and l2 doors, you may not realise where the switch is as it on the attendants panel and looks like 2 light switches with small arrows. Not sure about the zoom aircraft although the neos aircraft which are sister ships to the second 2 nc and na have electric doors.

The 757-300 has a tail skid and vacuum lavs, and the cargo doors are very different on the 767 ( the fwd lifts and drops into the hole, the aft is similar to the 757 )

On the 767 the turn off lights are in the wing root, the 757 are on the nose gear.

On the 767 you have access to the ee bay through the cabin.

The 767 has less flaps and a bulk cargo door on the lh side of the aircraft.

The best thing about the 767 rev's are an option of electrical opening, have worked on pw40000 with this and have heard that there is an option on the ge also.
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Old 17th Nov 2007, 09:50
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767 Inboard Ailerons (already mentioned) droop with Flap 5+.
767 Flap 1 is all Slat (no Flap)
767 Flap 30 and Flap 25 have overspeed (blowback) protection (Only on F30 with 757?)
767 at High GW has a Vref30+80 (min clean) in excess of Flap 1 Lim (250 kts)!
TOM has (had?) a pair of 762s with the -80C engines normally fitted to the 763. These 767-200Gti were a lot of fun on ferry flights, a 5000' stop height on a SID could be a problem! Automatics were way behind. Off MAN 23L you can get FL410 by BHX with pretty much normal operation (ie not hanging on the stall).
Oh, and did I mention the doors?
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Old 17th Nov 2007, 19:11
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For check Airman,

You forgot the world's worst oral question, "How does the recirculation fan work on the 757 versus the 767 and when does it operate and not operate?"

My response that got me in a bit of trouble was, "It operates all the time it is supposed to operate unless it is broken or malfunctioning and then we go into the log, find the proper maintenance code and write it up, right?"

I'd have given you full points for that
So what about load shedding, engine start, fire in the hold?? There are times when the re-circ fans switch off because they are supposed to!

To enter the door debate. I am a licenced a/c engineer rated on the 767 and I have yet to work on a 767 that does NOT have at least 1 electrically operated pax door. There are switches under the exterior handle and on the FAP for the relevant doors.
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Old 17th Nov 2007, 20:57
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Thanks.

I hate those dumb 'laundry list' oral questions which have nothing to do with anything except completing a rite of passage. On systems like the recir fan, there is little I can do if it does not operate when it is supposed to except write it up.

"What seven things happen when you pull the fire handles?" right.. so if one of the seven things does not occur, since they are automatic and can not be accessed, you are not going to be able to do anything about it anyway.

Like on the Citation II.. "What x things are fed by bleed air?" Right...

Now, a major question would be do you step up or step down on the 767? That is important. If one tumbles into the cockpit, it invariably creates a cloud of doubt and lack of confidence in the pilot by the F/As and any passenger seeing the event.. and if the Capt uses colorful language to mitigate the pain, that is likely to cause a letter by someone who is 'offended' by such brusque words.
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Old 19th Nov 2007, 04:39
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Oh, here's little gotcha. Nice oral question because it causes some confusion when seen on the line. (ask me how I know....friend asked and I had no clue )

767-200 flaps 5 T.O. inboard aileron doesn't droop
767-300 flaps 5 T.O. inboard aileron droops (remember, big jet needs all the lift it can get)
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Old 19th Nov 2007, 20:12
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767 has 5kVA HMG 757 has 10kVA HMG
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Old 20th Nov 2007, 04:47
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There is a difference between the PTU on the 757 which is a true power transfer system (try shutting down the left engine leaving the right running to hear the odd noise it makes !)

This transfers hydraulic power from the right to the left side (heavy) hydraulic essential services.

The PES or Pitch enhancement system on the 767 is completely different.
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Old 21st Nov 2007, 20:36
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For mono:

So what about load shedding, engine start, fire in the hold?? There are times when the re-circ fans switch off because they are supposed to!

He said "It operates all the time it is supposed to operate unless it is broken or malfunctioning"

So he's 100% right...
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