systems difference, 757 767

[Guest]

Hi,I have found a website, www.smartcockpit.com that describes the 767 systems in great detail. I was wondering if:1) What are the system differences between the 757 and 767, would the systems notes apply to both the 767 and 757 or are the differences too reat. 2)Will the manuals released with the 757 go into this much detail?one more question, I noticed on the pmdg website you are makeing the 767? how long will it take to develop? (ie are you going to use part of the 757 program or start from scratch?)thanks for any answersric

[marcom 139]

Hi Ric,As not being a member of PMDG, I can only answer part 1While most systems are similar, there are a few differences. For example the hydraulic system: On the 767 the main hyd. system is the center hyd. system. To it are the heavy systems applied, such as gear and flaps.On the 757, I believe it is the Left hyd. system (but could also be the right one, not sure)Also, the central hyd. demand pump on the 767 is an air driven pump (operated by bleed air). The 757 doesn't have this, only a PTU (power tranfer unit, uses the pressure in a different hydraulic system to drive the central hyd system without tranferring hydraulic fluid)Also, 767's are fitted with HMG's (hydraulic motor driven generator) which converts hydraulic pressure into electric power to drive the captain's main instruments. The 757 doesn't have this, only bat power to drive the captain's instruments should both AC buses fail.757's don't have fuel jettison, but not all 767's have that option either.I'm sure there are more differences, but there are the most substantial ones I can come up with.Hope this helped,Mark

[Jet Tech 31]

Hi Ric,The system differences between the 757 and 767 are so minimal that the Type Certificate for a pilot covers both A/C. From a pilots perspective, the cockpits are virtually identical. The only differences have mainly to do with the increased size of the 767 such as the addition of Inboard Ailerons, A Fuel Dump System and Heavier Gear and Air Conditioning systems. The Autopilot and FMC systems are identical. As far as the PMDG manuals, they are top notch compared to anything I have ever recieved with any other add-ons.Haven't heard any timelines yet for the 767 project but everyone at PMDG seems to be very busy trying to perfect the 757 to get it released. Hope this helpsRegardsPaul :-cool

[Guest GrantM]

Ric,There are too many differences to enumerate here. A few are major, but most minor. Let me summarize a few categorical differences:AIRCRAFT GENERAL- the 767's cockpit door has hinges on the left and opens into the cockpit.- the 767 has a bulk cargo door on the rear left side of its fuselage- the 762 has two overwing exits, the 763 & ER versions have 4- the 757 has 4 lavatories, the 762 has 5, the 763 has 6, the latter two 767 versions having elaborate waste control systemsELECTRICAL- there are somes specific electrical differences with the transfer buses, hydraulic motor generator, etc.NAVIGATION- there is a slight difference in way the IRS uses battery power on the 767ER compared to the 757 and even the 762/2- the MCP reference thrust switches and throttles idle during GA and AL are different- ADF & RDMI displays are differentFMC- the FMC source selector switch is configured differentlyFUEL SYSTEM- fuel tank design and functionality is different- 767 has a fuel jettison systemFLIGHT CONTROLS- slat/flap operations- rudder system- aileron operations- pitch/trim control systemsPOWERPLANT- 767 uses a GE CF6-80, the ER a P&W 4060 last I knew... same system design and operation as 757, but the EEC, engine indications and various value systems are different.- one major difference it that the 757 and the 767ER use EPR as the primary thrust setting while the 762/3 use N1There are major differences in the hydraulic system of the 767 mentioned by Mark above (left sys not right). Other differences are in the fire detection and protections systems, the landing gear, nose wheel steering, brake system, air conditioning, communications, pneumatic system, equipment cooling/cargo heat, ice detection and control systems as well as the oxygen delivery system.And of course the 767 is larger with more cargo and passenger capacity.A good part of these differences do not figure into the PMDG sim. I guess that I may have devulged more than you really wanted to know but maybe it is helpful.Grant

[rsrandazzo 6,353]

Grant-You forgot the obvious difference: A few hundred thousand pounds of aluminium..... :-lol(And for those keeping track of such things: 767 pilots have a greater number of F/A's to choose from than their 757 brethren...)Robert S. RandazzoPrecision Manuals Development Group http://www.precisionmanuals.com/images/coolcap.gifwww.precisionmanuals.com

[Guest GrantM]

Indeed! A 757 on steroids! :-lolGrant

[Guest]

FUEL SYSTEM- fuel tank design and functionality is different- 767 has a fuel jettison systemActually, not all 767's are configured with a fuel dump capability. It's a company option.POWERPLANT- 767 uses a GE CF6-80, the ER a P&W 4060 last I knew... same system design and operation as 757, but the EEC, engine indications and various value systems are different.- one major difference it that the 757 and the 767ER use EPR as the primary thrust setting while the 762/3 use N1Engines will vary depending on the aircraft. I don't believe there's one particular brand associated with the 767. GE's use N1 as the primary thrust indicator; PW and RR used EPR. Rolls Royce engines will also have an N3 indicator as well.Evidently GE has a patent on using N1 as the primary thrust indicator (seriously!)Jon (KSEA)

[Guest GrantM]

Jon,You are correct regarding the nuances of these items. The frame of reference for my input is Delta Airlines.Grant

[Jet Tech 31]

Robert Sorry to disapoint Rob but If your F/A's are like ours, Bigger A/C usually mean Senior F/A's :-lolPaul:-cool

[rsrandazzo 6,353]

Paul-OH! That's sure to start spirited discussion.....Doesn't quite work that way at UAL, as I recall....although we used to joke that the only way to get a SEA based F/A into the cockpit was to grease the door edges and place a Twinkie on the center pedestal.... :-lolI think our weight distribution was by domicile.... Yeah.... That was it.....Robert S. RandazzoPrecision Manuals Development Group http://www.precisionmanuals.com/images/coolcap.gifwww.precisionmanuals.com