B737 SP-77 Autopilot Interface
B737 SP-77 Autopilot Interface
(OP)
Hope someone can help!
We are an approved TC Aircraft Engineering Organization and,
I am installing a new Flight Management System in an older Boeing B737-200 jetliner. The 737 uses the Honeywell SP-77 autopilot. The SP-77 autopilot was fairly advanced for its day in that it calculated roll rate corrections based on aircraft speed.
My problem:
The new Flight Management System (FMS)also calculates roll rate corrections based on aircraft speed, so if I feed the roll steering output of the FMS into the autopilot (SP-77) without any other changes, then both units will apply a correction for speed, and the aircraft will turn too slowly and miss it's intended track.
How do I disable the Q-pot portion of the SP-77 input so that the SP-77 will ignore it's internal speed programming.
We are an approved TC Aircraft Engineering Organization and,
I am installing a new Flight Management System in an older Boeing B737-200 jetliner. The 737 uses the Honeywell SP-77 autopilot. The SP-77 autopilot was fairly advanced for its day in that it calculated roll rate corrections based on aircraft speed.
My problem:
The new Flight Management System (FMS)also calculates roll rate corrections based on aircraft speed, so if I feed the roll steering output of the FMS into the autopilot (SP-77) without any other changes, then both units will apply a correction for speed, and the aircraft will turn too slowly and miss it's intended track.
How do I disable the Q-pot portion of the SP-77 input so that the SP-77 will ignore it's internal speed programming.





RE: B737 SP-77 Autopilot Interface
The Areonautic forum would probably be a better place for your post.
Barry1961
RE: B737 SP-77 Autopilot Interface
DB
deja moo: I've heard that BS before.
RE: B737 SP-77 Autopilot Interface
blackwed: Don't worry, everything that is received as advice has to be thoroughly sanity checked. The question isn't as scary as it sounds. The problem is the age of the system (SP-77) - it's getting difficult to get advice on how to do certain things.
RE: B737 SP-77 Autopilot Interface
DB
deja moo: I've heard that BS before.
RE: B737 SP-77 Autopilot Interface