REF NAV DATA — Navaid Lookup

intermediate
📍 Route: EGLL approach briefing⏱ ~3 minutes📊 5 steps

Before flying any approach, real Boeing 737 pilots verify the inbound navaid frequencies on REF NAV DATA. Look up two VORs you would expect to use on the EGLL ILS 09L approach: DVR (Dover) for the initial fix and BIG (Biggin) for the final intermediate fix.

Start this scenario

Open the SimTuts 737 CDU trainer and select “REF NAV DATA — Navaid Lookup” from the scenarios list to walk through it step-by-step on the simulated keypad.

Open trainer →

Step-by-step: REF NAV DATA — Navaid Lookup

  1. Open the REF NAV DATA page. From IDENT, press INIT REF then LSK 1R for NAV DATA.

    REF NAV DATA is information-only. Unlike the Airbus MCDU RAD NAV page, the Boeing CDU does NOT tune the VHF NAV radios — that happens on the cockpit pedestal panel above the throttles. The CDU's job is letting the crew verify frequencies and positions before they need them in the cockpit.

  2. Look up DVR (Dover VOR). Type DVR and press 1L.

    DVR (Dover) is the primary VOR on the south coast of England — the gateway for traffic arriving Heathrow from Europe. Frequency 114.95 MHz. A 737 inbound EGLL from the south crosses DVR before joining the OCK or BIG arrival sequence.

  3. Now look up BIG (Biggin VOR). Type BIG and press 1L.

    BIG (Biggin) is a TMA VOR south-east of London Heathrow at 115.10 MHz, often used for the ILS 09L final intermediate. Verifying its frequency on REF NAV DATA gives you a sanity check before pulling out the approach plate — if the database disagrees with the plate, something is wrong (stale AIRAC, plate misprint, etc.).

  4. Look up a navaid that is not in the database to see how the page reacts. Type ZZZZ and press 1L.

    The CDU's navaid database only contains navaids in the current AIRAC cycle's coverage area. Idents not present return NOT IN DATABASE — useful confirmation that you typed the right code, or that an obscure navaid is too far from your current FMC region of operation. Always cross-check the AIRAC cycle on IDENT if a known navaid is missing.

  5. Look up DVR one more time to end on a known good value. Type DVR and press 1L.

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