If you are replacing a failed KI 256 with a new unit, you may not need a full manual re-installation. However, if you are installing into a new panel or swapping from a different indicator (e.g., KI 525), you must follow the complete process.
| Symptom | Likely Cause | Solution | |---------|--------------|----------| | OFF flag visible | No vacuum or gyro not spun up | Check vacuum line and electrical power | | Roll flag only | Missing roll command return (pin H) | Verify wiring continuity | | Bars stuck full scale | Command signal shield grounded at KI 256 | Remove ground loop — shield only at source | | Erratic attitude | Vacuum too high or low | Adjust regulator to 5.0 inHg | | No backlight | Voltage mismatch (28V to 5V lamp) | Install dropping resistor per manual Fig 6-3 |
The is an integrated internal air-driven vertical gyroscope and flight director indicator that serves as a cornerstone for several legacy automated flight control systems. It provides continuous pitch and roll attitude information visually to the pilot and electronically to the automatic flight control computer.
Leave a comment below or consult a Honeywell-authorized repair station. ki 256 installation manual
The KI 256 is not an isolated device; its installation is tightly coupled with the rest of the avionics suite.
Internally air-driven, requiring a regulated vacuum source of 4.5 in. Hg . Mechanical Installation
This article consolidates the essential installation steps, wiring diagrams, post-installation testing, and common pitfalls—based on official OEM documentation and field service experience. If you are replacing a failed KI 256
Designed for completely vertical panels.
The instrument utilizes a comprehensive multi-pin rear connector to interface directly with the flight computer. Technicians must carefully map out the following critical signal paths:
The BendixKing Flight Command Indicator (FCI) is a cornerstone of classic Honeywell/BendixKing flight control systems, including the KFC 150 , KFC 200 , KFC 225 , and KFC 250 . Functioning as both a vacuum-driven attitude gyro and a flight director display, its proper installation is critical for autopilot performance. System Overview and Requirements It provides continuous pitch and roll attitude information
: If the gyro takes longer than 8–10 minutes to right itself, the bearings may be contaminated or the internal vanes sticky, necessitating an overhaul. Autopilot "Porpoising"
| Category | Item | | :--- | :--- | | | Standard avionics tool set (screwdrivers, nut drivers, wire cutters, crimpers), panel‑cutting tools (if a new hole is required), 7/32″ and 5/16″ socket wrenches | | Electrical | Multimeter, insulation resistance tester (megger), crimping tool for D‑sub pins, soldering station (if required) | | Specialized | KTS‑150 Autopilot Test Set (or equivalent) for calibration and troubleshooting; a gyro test stand for pitch/roll calibration |
: The indicator supplies pitch and roll signals to flight computers like the .
: Employs internal electrical pickoffs (synchros) to transmit pitch and roll data directly to the autopilot computer (e.g., KC 295 or KC 192).