QFE Operations

James Albright (a former G450 driver)

Updated: 2014-03-16

The G450 makes QFE operations just about as easy as possible, but you still need to be careful about getting the V-speeds to box for takeoff, setting the pressurization system, and the EGPWS database. Of course you also have the matter of making sense of the instrument approach altitudes. The QRH and AFM checklists lead you through all but the last part. For that, see: Altimetry (Metric, QFE/QNH, and Other Variations).

Everything here is from the references shown below, with a few comments in an alternate color.

 QFE Takeoff Procedures

[G450 Airplane Flight Manual, §02-08-80]

  1. Set pilot and copilot altimeter settings to QNH (if available). If QNH is not available, set altimeter setting to achieve published field elevation.

  2. Perform Takeoff Initialization and verify Takeoff Data to be correct for the ensuing takeoff.

  3. On the Display Controller, manually ″box″ the takeoff V-speeds.

    You can perform the takeoff initialization using the FMS but the V-speeds will not automatically box if the displayed altitude (based on QFE) disagrees with the database field elevation.

    More on this: G450 Line Up Checklist.

  4. Select SEMI mode of pressurization and enter the QNH in the BARO CORR window of the Cabin Pressure Select Panel.

  5. Set desired Flight Level in the AIRPLANE/CABIN window along with the desired rate for cabin rate of change in the RATE LIMIT window.

  6. Set pilot and copilot altimeter setting to QFE for takeoff.

  7. During the TAXI checklist, verify that the FLIGHT mode is selected and that the DFRN PRESS does not exceed 0.30 PSID.

  8. Select TERRAIN INHIBIT switch to ON (ON legend illuminated) if geometric altitude is unavailable from EGPWS.

 QFE Climb Procedures

[G450 Airplane Flight Manual, §02-08-80]

  1. When clear of the traffic pattern, select AUTO V-speeds on the Display Controller.

  2. At Transition Altitude, select appropriate altimeter setting.

  3. Select AUTO mode of the CPCS.

  4. Select TERRAIN INHIBIT switch OFF (if previously selected ON).

 QFE Approach Procedures

[G450 Airplane Flight Manual, §02-08-80]

  1. NOTE: VNAV operations using QFE altimeter settings are prohibited. When conducting QFE, ILS or LPV approaches using the HUD, set the runway elevation to zero on the display controller HUD menu page.

  2. Set QFE altimeter setting when directed by ATC.

  3. Select SEMI mode of CPCS (Cabin Pressure Control System).

  4. Set QNH in the BARO CORR window of the CPSP (Cabin Pressure Selector Panel).

  5. Set published Landing Field Elevation in the LANDING ELEV window.

  6. Set desired RATE in the RATE LIMIT window.

  7. Select TERRAIN INHIBIT switch to ON (ON legend illuminated) if geometric altitude is unavailable from EGPWS.

  8. Verify CPCS is in LANDING mode. Verify DFRN PRESS less than 0.30 PSID prior to landing.

The AUTO mode doesn't like it in parts of Russia and China and gets confused. The SEMI mode can cope but you have to help it by translating QFE to QNH. See G-450 QRH NH-45 for the procedures.

 References:

Gulfstream G450 Aircraft Operating Manual, Revision 35, April 30, 2013.

Gulfstream G450 Airplane Flight Manual, Revision 36, December 5, 2013

Gulfstream G450 Maintenance Manual, Revision 18, Dec 12, 2013