August 10, 201114 yr 100 % sureISFD is Intergrated Standby Flight Display that has nothing to do with the Autoflight system it's only a Standby indicator for when everthing is dead. Yes it's Third source but only for the flight display. You need to engage the a third AUTOPILOT system to perform Autoland with rollout function. That is not posible on the 737. Because there are no 3 autopilots installed on 737. Mark Scheerman Boeing 737-6/7/8/900 Ground Engineer
August 10, 201114 yr I will clear up some confusion on the Autoland function.. You all know by now the procedures how to set an autoland up, but, no 737 has a autopilot function that will steer the aircraft once you've touched down.. The autopilot must be disconnected, you can disconnect even if you have the runway in sight and land manually, this is done frequently.. This is because the 737's autopilot doesn't have a direct link to the rudder.. 747,767,777 different story, will track the centerline until you disconnect.. ??????? I have flown with Ryanair for over 10 years. We can make a fail passive autoland if reqired to do so. Fred. Frederic Steiner.
August 10, 201114 yr 100 % sure ISFD is Intergrated Standby Flight Display that has nothing to do with the Autoflight system it's only a Standby indicator for when everthing is dead. Yes it's Third source but only for the flight display. You need to engage the a third AUTOPILOT system to perform Autoland with rollout function. That is not posible on the 737. Because there are no 3 autopilots installed on 737. with all due respect mark, think of airbus, that only has 2 autopilots, the 777 only has 2 autopilots, the Fokker 70/100 has 2 autopilots, yet those planes can do CATIIIB landings with rollout, at least im sure about the first 2 i mentioned. why then cant the 737 perform a CATIIIB landing with rollout? Why then does the 737 FCOM say that rollout mode is available with a fail operational system, why would PMDG make such an obvious mistake? im just saying... Bryan Richards "People depend so much on automation that they forget how to get the automation to work." B.W.
August 10, 201114 yr MD 11 can also do CATIIIb autolandings with only to AP, to continue Bryans list :) John Rubens
August 10, 201114 yr Just went back through the FCOM, it would make sense in thinking that the ISFD would be a sufficient inertia source and account for the reason why the 737 has the ability to have fail operational autoland, and why 737s with the analog standby flight instruments would have the fail passive autoland. For an aircraft to be CATIIIB certified it has to have 3 inertial units, in the 737s with the ISFD, you have 2 IRUs on the overhead, and 1 inertial unit that the ISFD has all to itself so those are CATIIIB, while the 737s with the analog standby flight instruments only have 2 inertial units the autopilot can use, the third is just a plain old gyro in the standby attitude indicator which would not be accurate enough to be used for autoland, hence those 737s would be CATIIIA. someone correct me if im wrong here please! Bryan Richards "People depend so much on automation that they forget how to get the automation to work." B.W.
August 10, 201114 yr with all due respect mark, think of airbus, that only has 2 autopilots, the 777 only has 2 autopilots, the Fokker 70/100 has 2 autopilots, yet those planes can do CATIIIB landings with rollout, at least im sure about the first 2 i mentioned. why then cant the 737 perform a CATIIIB landing with rollout? Why then does the 737 FCOM say that rollout mode is available with a fail operational system, why would PMDG make such an obvious mistake? im just saying... No all those airplane have 2x switch's to engage the Autoflight system's, but has 3 x Autoflight computers installed and the 737 has to 2x Autoflight computers installed. But I looked it up in the AMM of 737 and I was wrong to, the Airplane is a cat IIIB due to that yaw damper computer acts like a third Autoflight computer during a DUAL land approach and that is the rollout mode This is quote from the AMM. During rollout, the FCC calculates yaw commands to follow the runway centerline after touchdown. The yaw commands go tothe rudder servo to move the rudder and to backdrive the rudder pedals. This allows the yaw command to drive the nosewheel steering. The rollout mode engages when the gear altitude is less than 2 feet. The autopilot will disengage during rollout when groundspeed decreases to 40 knots Mark Scheerman Boeing 737-6/7/8/900 Ground Engineer
August 10, 201114 yr what? the NO LAND 3? I think only fail operational equipped 737s have this status message, it's displayed when the autopilot downgrades from fail operational to fail passive, that happened because the captain did something with the IFSD, i dont know if it was a reset or test, pretty cool video though! thanks for sharing! No all those airplane have 2x switch's to engage the Autoflight system's, but has 3 x Autoflight computers installed and the 737 has to 2x Autoflight computers installed. But I looked it up in the AMM of 737 and I was wrong to, the Airplane is a cat IIIB due to that yaw damper computer acts like a third Autoflight computer during a DUAL land approach and that is the rollout mode This is quote from the AMM. During rollout, the FCC calculates yaw commands to follow the runway centerline after touchdown. The yaw commands go to the rudder servo to move the rudder and to backdrive the rudder pedals. This allows the yaw command to drive the nose wheel steering. The rollout mode engages when the gear altitude is less than 2 feet. The autopilot will disengage during rollout when ground speed decreases to 40 knots thx Bryan Richards "People depend so much on automation that they forget how to get the automation to work." B.W.
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