Tips for Boeing pilots learning the MD-11

This article will attempt to explain some of the basic MD-11 systems methodology in terms of how similar features work on the Boeing 7x7 series aircraft you're likely more familiar with. If you're familiar with Airbus systems logic, some of that general knowledge will apply here, though be aware that many things on the MD-11 aren't exactly like the Airbus either.

MCP

The glareshield MCP (mode control panel) used to command the autopilot on a Boeing is called the FCP (flight control panel) on the MD-11.

Flight Mode Annunciator

The MD-11's FMA (located at the top of the PFD display) works slightly differently than you may be used to. Essentially you can see one of three colors present in each of the three FMA fields representing speed, roll and pitch. These colors have different meanings:

  • Magenta = the mode is following FMS generated commands.
  • White = the mode is following manual commands coming from the FCP.
  • Green = the mode is following commands associated with performing an autoland.

Keeping this color coding system in mind will quickly allow you to ascertain where the autopilot is getting its command information from at any time.

Autothrottle & autopilot relationship

The autothrottle and autopilot systems on the MD-11 are NOT independent of each other in the way that they are on Boeing aircraft. Before takeoff, pressing the AUTOFLIGHT button on the FCP arms both the autothrottle and the autopilot takeoff modes. Advancing the throttles manually past around 60% N1 will cause the autothrottle system to actually engage and begin controlling thrust. There is an audible click sound from the panel when this happens. After takeoff, press Autoflight again to do the equivalent of pressing one of the autopilot CMD buttons on a Boeing. This will actually give control of the pitch and roll modes over to the AP. From this point on, the two systems are completely unified and essentially operate as a combined system until disengagement at landing.

Disconnecting the autopilot & autothrottle

The MD-11 does NOT have "hard" switches on the FCP for disconnecting the AP and AT the way Boeing airplanes do. The only way to do disconnect them are via the soft disconnect switches located on the yoke and throttle in the real aircraft. There are key commands assignable in the PMDG menu for simulating these buttons. Upon pressing the AP disconnect, you will hear a disconnect warning, simply press the AP disconnect again to cancel this warning.

To reconnect the system, simply press AUTOFLIGHT on the FCP. This will reconnect BOTH the AP and AT.

The two AFS OVRD OFF switches on the FCP below the AUTOFLIGHT button are NOT regular autopilot disconnect switches like you may be used to on a Boeing! These switches completely disable the MD-11's automatics and you will lose other AFS functions that are normally available even with the AP disengaged such as ATS speed protection.

Flaps

The MD-11 is equipped with a unique variable flap lever position called Dial-A-Flap. It allows for any takeoff flap setting between 10 and 25 degrees to be set on the pedestal. 15 degrees is standard though it may be more optimal to use a different value depending on the situation. DAF is only used during takeoff, for approach it must be set to 15 degrees.

RTE, LEGS, & DEP/ARR

The MD-11's MCDU does not have dedicated pages for these functions the way a Boeing's CDU does. They are all handled through a single page associated with each waypoint called the Lateral Revision (LAT REV) page. Pressing the MCDU LSK to the left of a waypoint on the F-PLAN page brings you to the LAT REV page for that waypoint. This page allows you to do a number of things including inserting waypoints and airways, SIDs, STARs, and approaches.

It is very important to note that LAT REV should always be called up FROM the last waypoint prior to what you want. So if you want to add a STAR for instance, you need to bring up the LAT REV page for the last enroute waypoint before you want the STAR to start and add it from there.

The rough 1:1 comparisons between a Boeing FMC's pages are as follows:

  • RTE - Origin and destination airports are entered on the F-PLAN INIT page. The familar VIA and TO columns for airway entries are located by pressing the AIRWAYS page, accessed through a waypoint's LAT REV page.
  • LEGS - The F-PLAN page is roughly equivalent, though many modifications to the flight plan happen through a waypoint's LAT REV page and not directly on the F-PLAN page and scratchpad the way you'd do with a Boeing. The flight plan between your destination and your alternate appears at the bottom of the waypoint list, after the main origin to destination plan. The Boeing convention of making modifications to the route by line selecting waypoints from further downrange up into a new position does not apply here, you must use the LAT REV page's NEXT WPT prompt.
  • DEP/ARR - You insert SIDs, STARs, and approaches by using the SID and STAR pages, accessed through the LAT REV page. You should add a SID from origin airport's LAT REV page and a STAR from the last enroute waypoint's LAT REV page.

Direct To

Going direct to a waypoint in the MD-11 is a dedicated function on the MDCU, accessed by pressing the DIR INTC key. You can NOT go direct by line selecting a waypoint to the top of the F-PLAN page the way you would do on a Boeing CDU. Simply press DIR INTC, then line select the waypoint into the box at the top or type it into the scratchpad. Confirm it and off you go.

HDG HOLD & HDG SEL

The MD-11's version of these modes are accessed by either pushing the heading knob to hold current heading, or pulling the knob to fly the selected heading in the box.

ALT HOLD & LVL CHG/FLCH

The MD-11 has modes roughly equivalent to both Boeing modes that can be engaged by pushing the altitude knob to hold the current altitude or pulling it to engage a pitch-for-speed mode similar to Boeing's LVL CHG or FLCH modes. It will climb or descend and capture the altitude in the window.

LNAV

This is simply called NAV on the MD-11's FCP and the button is located below the heading knob.

VNAV

The MD-11's version of VNAV is called PROF, short for "profile" and can be activated with the PROF button below the altitude knob.

Speed modes

Pushing the speed knob will hold the current airspeed, pulling it will fly the selected speed in the window, and pressing the FMS button will blank the window and allow the FMS to command speed.

FMS speed targets

The MD-11 is unique in a couple of respects with regard to FMS speed targets and restrictions. All speed targets are treated as AT OR BELOW, which means that you could end up crossing at a lower speed than what you'd entered in for a particular waypoint if the FMS deems it necessary. The FMS is smart and if you tell it to descend steeply and decelerate at the same time, the deceleration will get moved backwards along the route to account for the decent that's required later on. Don't be alarmed if you see this propagation of lower speeds up into waypoints you didn't set restrictions for, it's just the airplane helping you manage your energy.

Speed control during approach

Boeing pilots will be used to exercising manual control over the aircraft's speed during approach by using the MCP speed window. This is NOT how the MD-11 is designed. It is completely normal for the MD-11 to land with the speed window closed and under full FMS control.

The FMS calculates approach speed on the basis of a few rules during the approach sequence, each distance listed is the point during the approach where these speed reductions must occur by, but they can occur earlier if calculations demand it.

  • 15 to 11 miles - Slats +20.
  • 7 miles - Dial-a-flap +20
  • 6 miles - Flaps 28 +5
  • 5 miles - landing flaps +5

The aircraft will automatically decelerate to these speeds provided you have the aircraft configured correctly as far as flap settings. You will see a hollow magenta circle on the speed tape indicating that it's time to deploy the next flap setting.

Autoland

Performing an autoland in the MD-11 is as simple as pressing the APPR/LAND button located on the FCP above the AUTOFLIGHT button. Provided you are tuned to an ILS frequency that contains both a localizer and glideslope, (which is done automatically by the FMS) the plane will execute an autoland unless you take over manually.

The type of autoland is determined when you descend below 1,500 ft AGL as follows:

  • If all your systems are opering normally you will see a green DUAL LAND annunciation on the PFD FMA indicating a full CAT III autoland.
  • If you have failures that are not critical for the autoland (for example, one of the two autopilots inoperative or one HYD system failed) a white SINGLE LAND will be annunciated and a CAT II autoland will apply.
  • If you have critical system failures, or excessive deviation from LOC or GS a white APPR ONLY will be annunciated and the autoland function will not be available. The aircrtaft will continue to track LOC and GS, but autopilot will disconnect at 100 ft AGL.

IMPORTANT
In an autoland the AP remains engaged after touch down to keep the aircraft aligned to the runway. At the end of the rollout you should manually disengage the autopilot, otherwise you will not be able to taxi, since the AP will still try to keep you on runway track.

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