King Air Pro Line 21 Navigation Architecture & Maintenance Evidence
Explore the named components, make a prediction, then connect the supplied result to the system. This workshop adds coached practice alongside the course handbook and assessed lab.
Follow the navigation evidence
Separate a radio measurement, a receiver data page, a selected navigation input and a completed file transfer. Click each function to see its role, then predict and interpret three fictional records. These formative exercises supplement the course handbook and assessed lab.
Find the Pro Line 21 navigation displays and radio tuning unit
First find the radio tuning unit and the main display positions. Then follow the named normal-operation paths below. These dark screens provide no frequency, navigation-mode or equipment-health observation. This is an ungraded orientation, not an aircraft control simulation.
Beechcraft King Air 350. Cockpit (4104672117).jpg by Aleksandr Markin, CC BY-SA 2.0. Photograph unchanged; interactive labels by WWAOG. Photograph and labeled view: CC BY-SA 2.0; assessment text remains separate.
Scroll across the photograph to inspect the panel, or open the full-size cockpit photograph ↗. The named buttons below also select every teaching point.
Choose a numbered item
Find it in the photograph, then read its action, purpose and connection to the rest of the system. You can also choose a named item in the list. Keyboard users can use Tab and Enter or Space.
Follow the FMS path, then compare the separate radio-navigation path
These are functional relationships in the supplied B300/B300C Pro Line 21 navigation description, not wire or pin connections. The radio-navigation path is separate from the FMS steering path.
Enter a flight-plan item at the CDU-3000
The CDU is the crew interface in the pedestal, outside this photograph. Alphanumeric entry appears in its scratchpad; a line-select key transfers that entry to the appropriate field. A typed scratchpad entry has not yet been transferred.
GPS-4000A/S sends navigation data through IAPS
The GPS antenna supplies satellite signals to the GPS receiver. The receiver supplies position, velocity and time through the IAPS input/output data concentrators to the FMS. On the CDU GPS page, missing or flagged position data is replaced by yellow dashes.
FMC-3000 computes navigation and steering
The FMC in IAPS uses navigation sensors for point-to-point lateral navigation and vertical navigation. The FMS sends lateral and vertical steering to the Flight Guidance Computer. A steering output is a separate observation from autopilot engagement or aircraft movement.
Compare RTU, NAV receiver and display observations
This is the separate radio-navigation path: the RTU, navigation receiver, antennas and Adaptive Flight Displays work together to depict the navigation situation. Compare the control selection with the actual indication; keep the receiver's audio output to the Audio Integrating System as a separate observation.
Expected normal response: On the CDU GPS1 page, position data, date and time are displayed in green. Missing or flagged GPS position data is replaced by yellow dashes. Those named indications help distinguish the displayed GPS data from a typed entry or a tuning selection; the dark cockpit photograph cannot demonstrate this response.
Study reference: Textron 130-590031-11: 34-31-00 p.1 (actual PDF 113); 34-51-00 p.1 (actual PDF 161); 34-61-00 p.1 (actual PDF 188). Functional relationships, not a wiring diagram or supplier checkout procedure.
King Air 350 Pro Line 21 cockpit example. The supplied B300/B300C navigation chapter applies to FL-381, FL-383 and after; FM-12 and after, with equipment-specific exceptions. The photograph establishes visible locations, not its aircraft serial, software or complete installed equipment. The pedestal CDU and remote navigation computers are outside this photograph.
This guided photo activity explains the visible equipment. Selecting a label does not operate an aircraft control or record course completion. Continue with the system diagram and supplied fault record to practice troubleshooting.
Navigation functional relationships, not a serial radio chain or physical bus map. NAV, DME and GPS are separate functions. The NAV–DME link denotes frequency pairing, while GPS reaches the FMS through the IAPS input/output data concentrators.
Green outlines identify components named in the selected exercise record; they do not indicate a healthy component.
Named connections and what each arrow means
- NAV radio function → DME-4000 range functionTask sequence: Associated VOR/ILS frequency pairing
- GPS-4000A/S receiver → FMC-3000 computationInformation / signal: Position / velocity / time via IAPS I/O
- GPS-4000A/S receiver → CDU-3000 control / displayInformation / signal: Backup receiver data pages
- CDU-3000 control / display → FMC-3000 computationTask sequence: Entry and selected sensor use
- CDU-3000 control / display → NAV radio functionTask sequence: Stand-alone radio control
- Installed DBU loader → FMC-3000 computationTask sequence: Identified target and file transfer
NAV radio function
Receives the navigation-radio information used to depict the navigation situation.
How it works with the rest
The NAV-4000 hosts VOR/ILS and ADF functions, including VOR/localizer, glideslope and marker beacon reception. It operates with tuning, antennas and adaptive flight displays; VOR/localizer and marker beacon audio go to the audio integrating system. The related removal/test tasks name NAV-4000/NAV-4500 installations. A valid observation of one received function does not establish every other function or a separate DME measurement.
What the evidence must show
Identify the installed receiver and observed function. A paired frequency is a tuning relationship, not proof that all navigation receivers share one measurement.
Selected: NAV radio function
Follow the change through the system.
Fictional optional dual-GPS installation: the on-side GPS1 page shows green position data. FMS1 GPS CONTROL is then set to deselect all GPS usage. Predict whether receiver-page availability and selected FMC use must become the same state.
Before the recorded change
GPS1 data page: green position. Pending control state: all GPS usage deselected on FMS1 GPS CONTROL. No receiver hardware failure or data flag is supplied.
Next observation
Choose your prediction before revealing the supplied result.
Reference: Textron 130-590031-11, 34-51-00 p. 1, April 1, 2018; supplied Chapter 34 PDF p. 161. Defines optional installations, GPS1 indications, GPS CONTROL selection and receiver-versus-FMC comparisons.
Course applicability and study references
The supplied B300/B300C Pro Line 21 NAV-4000/NAV-4500, DME-4000, GPS-4000A/S, FMC-3000 and CDU-3000 tasks, effectivity FL-381, FL-383 and After; FM-12 and After, with installed equipment verified. The DBU-5000 load record uses its later branch: FL-600 through FL-602, FL-604 and After; FM-27 and After. Optional dual equipment is stated within each record. Fictional measurements are supplied examples, not aircraft acceptance limits or operating instructions.
- Separate NAV and DME functions
Textron 130-590031-11, Super King Air B300/B300C Maintenance Manual, 34-31-00 p. 1 and 34-31-01 pp. 401/501; 34-53-00 p. 1, April 1, 2018; supplied Chapter 34 PDF pp. 113–116 and 166. Defines NAV functions, DME line-of-sight range and frequency pairing.
- GPS availability and selected use
34-51-00 p. 1, April 1, 2018; supplied PDF p. 161. Defines receiver/antenna installation options, the IAPS output path, on-side data pages, selected GPS use and receiver-versus-FMC comparisons.
- FMC and CDU roles
34-61-00 p. 1 and 34-61-01 p. 501, April 1, 2018; supplied PDF pp. 188 and 191. Separates computation, control/display, scratchpad transfer and the post-replacement database/test relationship.
- Loader identity and per-FMC evidence
34-57-00 p. 1; 34-59-00 p. 1; 34-63-00 p. 201; 34-63-01 p. 201, April 1, 2018; supplied PDF pp. 176, 181 and 195–196. DBU-4100 and DBU-5000 are distinct installed branches. The latter task defines named load stages, its blinking-yellow media caution, the separate-FMC requirement and the separate WRITE LOGS result.
Original learning diagrams and supplied training records explain the stated relationships. Current aircraft-effective instructions and authorization govern actual maintenance.