Re: FMC's on Boeing planes

From: (Robert Dorsett)
Organization: Netcom Online Communications Services (408-241-9760 login: guest)
Date:         09 Jul 94 21:18:34 
References:   1
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In article <airliners.1994.1429@ohare.Chicago.COM> (Morten Norby Larsen) writes:
>A while ago, somebody posted a reference to a book about the Smith
>Industries Flight Management Computer (FMC) on a 737 (which I lost,
>could some kind soul please send it to me again, e-mail address below?).

My review is appended.  The book is very much alive, and still being 
updated. I have also appended a review of a videocassette outlining the
767 FMS (simulator flight from LAX to SFO).

>I know very little about these creatures, but would like to know more,
>especially about the FMC's on board a 767. For instance:
>Are there more than one supplier, and if so, what are the differences
>from one supplier to another - and from one A/C type (e.g. 737/767) to
>another? (Interface, functionality...)

Honeywell supplies all FMCs for all Boeing aircraft except the 737.  The
737 is exclusively Smiths Industries.  All Airbus FMCs are Honeywell.  
Corporate-jet FMCs tend to be produced by smaller companies.

Similarities are covered by Bulfer's book, but in essence, every FMC is
unique.  My conversations with him have been marked by a steadfast refusal
to generalize *anything*. :-)  

But, generally, FMC's are used for managed flight; the Airbus Universe is 
different from the Boeing Universe (the Boeing Universe is regarded as more 
user-friendly).  The Smiths and Honeywell FMC's share many features within 
the Boeing Universe, since Boeing specs them.  Apart from that, you really 
have to go into it feature by feature, and even revision by revision.

>How much of the flight is/can be undertaken by the FMC? I am thinking
>about take-off, climb, cruise, initial approach and so forth. For
>instance, does an automatic landing have anything to do with the FMC?

Depends on the airplane.  The FMC can get the airplane into the general
vicinity to where the autopilot's autoland features can take it the rest
of the way.  

In general: 

flight control system -> maneuvers the airplane.
	controllable by: pilot, autopilot.

autopilot: commands the flight control system.
	controllable by: pilot (selected flight), fms (managed flight).

fms: navigates the airplane according to a specified flight plan.
	controllable by: pilot.

The autopilot is a *dumb* device, short-term control only, specified short-
term effects only.  The FMS is MUCH more complex, with its own intelligence,
navigation resources (air data computers, IRS's, VOR/ILS inputs), etc, and

Robert Dorsett                                              

Newsgroups: sci.aeronautics.airliners
From: (Robert Dorsett)
Subject: REVIEW of _FMC User's Guide_
Message-ID: <airliners.1992.176@ohare.Chicago.COM>
Date: 17 Dec 92 03:35:17 PST

Title: FMC User's Guide: Advanced Guide to the Flight Management Computer

Author: Bill Bulfer

Published by:

	Bill Bulfer
	Technical Publications
	2031 River Falls Drive
	Kingwood, TX  77339

Cost: $40.  Optional update service, $12.

Pages: ~200; extensive illustrations.  It is designed to be carried in a 
flight bag, printed on "half-pages," in a flexible, compact, three-ring 


The Flight Management System is the "heart" of modern transport operations.
It is the core of navigation functionality and automatic flight control,
and permits a flight to be flown very economically.  Despite its overall
usefulness, standard interfaces leave something to be desired: consequently,
a high proportion of training time is currently dedicated to the FMS, at the
inevitable expense of other systems.  There is evidence this training is 
somewhat lacking, with hands-on time limited.  This means that "real 
learning" occurs in-flight, on the job.  This is not a desirable situation, 
since it increases heads-down operations, thus decreasing the situational 
awareness of the pilot(s).

The author, a Continental 737 pilot, wrote the book (manual, really) in 
an attempt to provide a high-quality, goal-oriented overview of FMS functions, 
as a supplement to airline training programs.  It is a result of his own 
exposure, extensive research, and feedback from the manufacturers.

The book is oriented around the Smiths Industries FMS, in use on the 737, 
but the author explicitly addresses differences and similarities with the 
Honeywell lineage, which is in use on more types of airplanes.

The book is written for pilots, but may also be of interest to researchers
and hard-core airliner enthusiasts.  It is oriented around CDU (control data 
unit) operation, but includes mode control unit notes, where appropriate.  As
indicated, it's heavily goal-oriented, showing precisely what the pilot would
see on various screens, with relevant fields highlighted, as he attempts 
to set up a solution to a given problem.

An update service is available, on a yearly basis, for a nominal fee.  
Bulfer plans on issuing updates about every six months: the current update 
is about 80 pages.  He's also working on a "final exam," to go with the 

I heartily recommend this book for anyone seriously interested in the 
intricacies of FMS operation.  It is one of the best pilot-oriented 
technical publications I've ever seen.

Disclaimer: I have no financial connection with or interest in this project; 
I'm just a very satisfied customer.  I received my copy in September, and
have been working through it (slowly :-)) since then.

Robert Dorsett!!rdd


Date: 20 Oct 91 14:03:31 GMT
From: (Robert Dorsett)

THE GLASS COCKPIT.  80 min.  $49 + $3 S&H.  Aviation & Space Videos,
316 N.  12th St., Sacramento, CA  95814.  800-348-9933.

"The Glass Cockpit" is an introduction to the Flight Management System
(FMS) concept, using the 757/767 cockpit environment as a practical
example.  FMS's comprise the backbone of the operation of modern jet
aircraft, and were introduced beginning in the early 1980's.

The setting is that of an operational United Airlines 767 flight
simulator.  The tape follows this approximate format:
        - Introduction to displays:
                - electronic attitude director indicator (EADI). 
                - Nav display (EHSI).  
                - upper Engine Indication and Crew Alerting System
                - lower EICAS.  
        - Intro to autopilot mode control panel.  
        - Detailed coverage of the Control Data Unit (longest segment).

The tape finishes with an event-oriented flight from LAX to SFO,
including a demonstration of how to use the FMS to accomodate two
changed clearances: one at departure, and one inbound.  It finishes
with a CAT IIIA landing.  It's exclusively demonstrated on the
instruments: the only "out the window" view is when the airplane
crosses decision height (and even that's overlayed on what we'd be
seeing on the EADI).

The narrator/emcee sits in the captain's seat, showing us around the
cockpit and systems.  A split-screen format is frequently used, as is a
screen pointer.  The coordination of the presentation of systems is
good: changes made through the CDU or autopilot mode panel are shown on
the EADI or EHSI.

Overall, the quality of the tape comes across as somewhat amateurish:
there's a lot of background noise from the simulator, for instance, so
the narrator has to speak up, which in turn sounds kind of
stiltish--rather like those 50's and 60's-era documentaries we all had
to sit through in grade school. :-)  

A major failing is that we *see* changes to the CDU through the *right* 
CDU.  However, the majority of the changes are *made* through the *left* 
CDU.  Thus, we don't see EXACTLY how items are "put into the scratchpad" 
or assigned to other items (an operation which, surprisingly, looks a lot 
like Mac- style Cut & Paste).  The narration usually goes "Now, we'll 
put line L# in the scratchpad, then put it in over line R#..."  But we
don't really see the mechanics involved.

The strong point is the quality of the amount of data on the subject
matter itself: it's an excellent introduction to the systems.  The
narrator is clearly a proponent of FMS systems, but one has got to
wonder whether his basic points (smarter, more economical, faster) are
presented effectively: there's a LOT of heads-down workload in that
simple run from LAX from SFO.  It's an unrealistic example for a 767,
but we know that 737s (and MD-80s, and, eventually, A320s) have to do
this all the time.  And the CDU comes across as the User Interface from
Hell: slow, and with a hodgepodge of text sizes and styles.  It's very
difficult to tell what the "active" fields are, and what the labels are
(it's bad enough that I started to suspect parallax between the
selector buttons and fields from the camera angle, but when we actually
see what the fingers are doing, it turns out that it really is that
bad).  Even the narrator gets "lost" a couple of times.  But I
digress.  Again. :-)

Overall, the tape's worth having, for those interested in glass


CAT IIIA   An ILS landing, with no decision height, and RVR of 700'.  
CDU        Control Data Unit.  Primitive, keyboard-driven interface between 
           pilot & FMC.  
EADI       Electronic Attitude Director Indicator.  
EHSI       Electronic Horizontal Situation Indicator.  Shows A/C plan view
           relative to navaids and waypoints.  
EICAS      Engine Indication and Crew Alerting System.  For engine and systems 
           monitoring, systems messages, and checklists Replaces F/E and 
           traditional center instruments.  
F/E        Flight Engineer.
FMC        Flight Management Computer.  Central aspect of the FMS.  
FMS        Flight Management System. The sum total: FMC, CDU, IRS, displays, 
ILS        Instrument Landing System.  A way of landing airplanes in low 
IRS        Inertial Reference System.  Black box that tells pilots where the 
           plane is.  
LAX        Los Angeles International Airport.  
RVR        Runway Visual Range.  Visibility down the runway, measured by 
           mechanical instruments.  
SFO        San Francisco International Airport

Disclaimer: I have no personal or business connection whatsoever with
Aviation & Space Videos, Inc, or any of its products.