Ki | 256 Installation Manual

The BendixKing KI 256 Flight Command Indicator Go to product viewer dialog for this item.

is a core component of many legacy flight control systems, including the KFC-150, KFC-200, KFC 225, and KFC 250. It functions as a self-contained vertical gyro that displays aircraft pitch and roll attitude while supplying these reference signals to the flight computer. Core Technical Specifications

Power Inputs: +14VDC or +28VDC (0.7AMP max); 10VAC at 430Hz (0.2 amp max). Weight: Approximately 3.3 lbs.

Panel Tilt: Available for zero-degree or 8-degree instrument panels.

Display Features: Single cue command bar for flight director pitch and roll commands. Installation & Maintenance Requirements Because the Go to product viewer dialog for this item.

is a critical flight instrument, installation must be performed by an FAA-approved mechanic.

Mounting: The unit is typically front or rear-mounted in a standard 3-inch ATI opening. Interfacing

: The indicator supplies pitch and roll signals to flight computers like the KC-295.

Service Bulletin 11 (SB 11): This critical modification replaces the command bar PC board to reduce "loading effects" on pitch and roll outputs. It is required in most installations where the is paired with the KC-192 autopilot computer.

Static Safety: All disassembly or assembly must occur at a static-safe workstation to protect internal modules. Modern Alternatives Pilots looking to replace the aging

—which can be expensive to overhaul—often consider digital upgrades. Note that simple electronic flight instruments like the Go to product viewer dialog for this item. cannot directly replace a

in most legacy autopilot systems because they do not provide the necessary flight director signals. Certified alternatives typically include: Aspen Evolution 1000 Pro

: One of the few systems that includes the flight director capabilities needed to replace the Garmin G500 Go to product viewer dialog for this item.

/G600: Often requires a GAD 43E adapter to interface with legacy autopilots. ki 256 installation manual

For detailed wiring diagrams and step-by-step procedures, refer to the KI 255/256 Maintenance Manual (P/N 006-05146-XXXX) or the specific BendixKing Flight Control System Installation Manual for your aircraft.

KI 256 Flight Command Indicator Mod | PDF | Computing - Scribd

KI 256 Installation Manual Report

Introduction

The KI 256 is a sophisticated instrument designed for precise measurement and indication of various parameters. This report provides a comprehensive overview of the installation procedures for the KI 256, ensuring a successful and efficient setup.

Pre-Installation Requirements

Before proceeding with the installation, ensure that:

1. Qualified Personnel: Only authorized and trained personnel should attempt to install and configure the KI 256.
2. Environmental Conditions: The installation area should have a stable temperature range (20°C to 30°C / 68°F to 86°F), relative humidity (≤ 80%), and be free from excessive vibrations.
3. Power Supply: A stable power supply (24V DC, 1A) is required, with a recommended wiring and circuit protection.

KI 256 Installation Steps

Step 1: Unpacking and Inspection

1. Carefully unpack the KI 256 from its shipping container.
2. Inspect the instrument for any damage or defects.
3. Verify that all components, including the user manual, are included.

Step 2: Mounting

1. Panel Mounting: The KI 256 can be panel-mounted using the provided mounting hardware.
   • Cut a rectangular hole (154mm x 74mm / 6.1" x 2.9") in the panel.
   • Insert the instrument into the hole and secure it using the provided clips.
2. DIN Rail Mounting: The KI 256 can also be mounted on a DIN rail (35mm / 1.4").
   • Align the instrument with the DIN rail and snap it into place.

Step 3: Electrical Connections

1. Power Supply: Connect the power supply (24V DC) to the designated terminals (L+, L-).
2. Sensor Connections: Connect the sensors or input devices to the designated terminals (I1-I6, V1-V6).
3. Communication Interfaces: Connect any optional communication interfaces (RS-232, RS-485, USB).

Step 4: Configuration and Calibration

1. Initial Power-Up: Apply power to the KI 256 and allow it to initialize.
2. Configuration: Configure the instrument using the front panel buttons and menu system.
3. Calibration: Perform calibration procedures as outlined in the user manual.

Step 5: Final Checks

1. Verify Functionality: Test the KI 256 to ensure proper operation and measurement accuracy.
2. Check for Error Messages: Review the instrument's display for any error messages or alerts.

Conclusion

The successful installation of the KI 256 requires careful attention to pre-installation requirements, mounting, electrical connections, configuration, and calibration. Following these steps and consulting the user manual will ensure optimal performance and accuracy of the instrument.

Recommendations

• It is recommended to perform regular maintenance and calibration checks to ensure continued accuracy and reliability.
• Refer to the user manual for detailed operating instructions and troubleshooting procedures.

Revision History

• Revision 1.0: Initial document release.

Document Control

• Document ID: KI 256 Installation Manual
• Revision: 1.0
• Date: [Current Date]

Please consult the manufacturer or authorized representative for any questions or concerns regarding the installation and operation of the KI 256.

The BendixKing KI 256 is an internally air-driven Flight Command Indicator that serves as a central component in BendixKing flight control systems like the KFC-150, KFC-200, KFC 225, and KFC 250. It provides a pictorial display of aircraft pitch and roll while supplying attitude reference signals to the flight computer.  Core Installation Specifications 

Mounting: The unit is front-panel mounted and available for either zero-degree or 8-degree instrument panels.

Dimensions: Approximately 7.31 in (L) x 3.55 in (W) x 3.37 in (H). Weight: Roughly 3.3 lbs.

Power Requirements: Operates on 14VDC or 28VDC (0.7AMP max) and 10VAC, 430Hz (0.2AMP max).

Pneumatic Input: Requires a regulated 4.5 in. Hg air source; proper filtration and regulation are critical for gyro operation.  Installation & Maintenance Procedures 

Handling Precautions: Gyros are sensitive; they should be transported in original containers or hand-carried in their normal operating attitude to avoid bearing damage.

Alignment: If a system alignment is required (e.g., in a KFC 200 system), a gyro extender cable is typically used to connect the indicator to the airplane harness while mounting the gyro on a level tilt stand. The BendixKing KI 256 Flight Command Indicator Go

Testing: Post-installation, a functional test must be performed. Testing often involves specialized equipment like the KTS 150 Flight Control System Test Set.

Modifications: Specific updates, such as Service Bulletin KI 256-11, may require replacing the internal PC board to reduce loading effects on pitch and roll outputs.  Documentation & Resources 

For official technical data, refer to the following BendixKing and third-party technical archives:  Downloads & Manuals - BendixKing

Part 8: The Future – Should You Still Install a KI 256?

As of 2025, the KI 256 is considered legacy/obsolete. Honeywell no longer manufactures new units, and repair costs (typically $1,500-$2,500) often exceed the value of the gyro. However, for vintage Beechcraft Barons, Cessna 340s, and Piper Navajos, keeping the KI 256 running is still common.

If you are planning a new installation from scratch, consider alternatives:

• Mid-Continent MD302 SAM (Standby Attitude Module): Provides attitude to KCS 55 via converter.
• Garmin G5 or GI 275: Replace the entire KCS 55 system, eliminating the KI 256.

But if you are restoring a classic panel and have a working KI 256, a careful, by-the-manual installation will yield reliable service for another 500-1000 hours.

Final Verdict: Don’t Fly Without the Manual

The KI 256 is a precise, analog-era instrument that demands respect during installation. Skipping steps in the KI 256 installation manual—especially the gyro nulling and synchro phasing—will result in degraded autopilot performance, uncommanded pitch oscillations, or a failed inspection.

Whether you’re a weekend warrior or a career avionics technician, keep a copy of 006-10593-0000 in your hangar library. Your autopilot will thank you.

Reliable Sources:

1. Honeywell Aerospace Technical Publications – Request a quote via their legacy support form.
2. Aviation Archives – Sites like Essco Aircraft or Aircraft Spruce sometimes sell reprints.
3. Your local repair station – Many shops (e.g., Duncan Aviation, Northern Airborne) provide copies to customers undergoing installation.
4. FAA DER reports – For field approvals, the manual is often attached as a referenced document.

Warning: Avoid random PDF downloads from unverified forums. Outdated revisions (pre-Rev 8) contain incorrect pinouts for late-model autopilot computers.

KI 256 Connector Pin Assignment (Partial – Critical Signals)

| Pin | Signal | Wire Color (King harness) | Notes | |------|-----------------------------|----------------------------|---------------------------------------------------| | 1 | +28V DC Erection | Red/White | Powers the vertical erection circuits. | | 2 | Gyro Spin Motor (115V AC) | Brown/Black | 400Hz from inverter or alternator. | | 3 | Gyro Neutral (AC return) | Black | Must be isolated from DC ground. | | 4 | Roll Syncro Stator S1 | Blue | To KI 525A or autopilot computer. | | 5 | Roll Syncro Stator S2 | Yellow | | | 6 | Roll Syncro Stator S3 | Green | | | 7 | Pitch Syncro Stator S1 | Orange | | | 8 | Pitch Syncro Stator S2 | White/Orange | | | 9 | Pitch Syncro Stator S3 | White/Green | | | 10 | DC Ground | White/Black | Also connects to gyro case ground. | | 11 | Flag Output (Normally Open) | Gray | Opens on gyro fail, triggers warning flag. | | 12 | Flag Common | Black/White | | | 13 | +28V DC (Aux) | Red | For lighting (if dimmer not used). | | 14 | Lighting Dimmer Bus | Violet | 0-5V DC typical. |

Critical Warning from the Manual: Do not combine AC ground and DC ground. The KI 256 uses separate returns. Combining them creates ground loops that induce 400Hz noise into the syncro outputs, causing HSI oscillations.

5. VACUUM SYSTEM CONNECTION

• Connect 1/4-inch ID vacuum hose from regulated vacuum source to rear barbed fitting.
• Required vacuum at instrument inlet: 4.5 inHg min, 5.5 inHg max.
• Install an in-line vacuum filter (P/N 145-00005-00) within 6 inches of the KI 256.
• Verify vacuum regulator is not shared with pneumatic autopilot servos without a check valve.

Post-connection test: With engine running and gyro powered, vacuum gauge at KI 256 case must read steady 5.0 ±0.2 inHg after 5 minutes.

Step 2: Gyro Caging

Apply 28V DC and 115V AC. Allow 3 minutes for spin-up. Depress the “CAGE” button on the KCS 55 controller for 10 seconds. Qualified Personnel : Only authorized and trained personnel

4. Electrical Wiring & Pinout (The Heart of the Manual)

The KI 256 installation manual dedicates five pages to wiring. Below is the essential pinout for a standard KFC 150 autopilot integration. Always verify against your specific serial number.

| Pin | Function | Signal Type | Wire Gauge | |-----|----------------------|----------------------|------------| | 1 | Power Input (14V or 28V) | DC Power | 22 AWG | | 2 | Power Ground | Ground | 22 AWG | | 3 | Pitch Gyro Signal (3.8V RMS) | 400Hz AC | 24 AWG shielded | | 4 | Pitch Gyro Reference | 400Hz AC Return | 24 AWG | | 5 | Roll Gyro Signal | 400Hz AC | 24 AWG shielded | | 6 | Roll Gyro Reference | 400Hz AC Return | 24 AWG | | 7 | Slip/Skid Sensor (+/- 150mV) | DC Analog | 22 AWG twisted | | 8 | Slip/Skid Return | DC Ground | 22 AWG | | 9 | No Connection | N/A | N/A | | 10 | Flight Director Pitch (Command) | 0-5V DC | 22 AWG shielded | | 11 | Flight Director Roll (Command) | 0-5V DC | 22 AWG shielded | | 12 | Synchro Stator C (Roll) | 26V 400Hz | 24 AWG | | 13 | Synchro Stator B (Roll) | 26V 400Hz | 24 AWG | | 14 | Synchro Stator A (Roll) | 26V 400Hz | 24 AWG | | 15 | Lighting Power | 5V or 14V AC/DC | 22 AWG |