Risks articles

From:         ernst@Tymnet.COM (Dennis Ernst)
Date:         28 Jun 93 22:35:02 PDT
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I saw the following articles in comp.risks and thought the group might
be interested:

Date: Thu, 20 May 1993 11:38:26 +0100
From: Brian.Randell@newcastle.ac.uk
Subject: Flight control computers `to bypass pilots'

  [In the following item, the statement: "The system also ensures that no
  mistakes are made" especially caught my eye! And I imagine that RISKS
  readers such as Don Norman will have something to say about: "[Pilots] will
  control by exception, in other words leaving all routine tasks to be done
  automatically by the computers."  Brian Randell, Dept. of Computing Science,
  University of Newcastle, Newcastle upon Tyne, NE1 7RU, UK
  Brian.Randell@newcastle.ac.uk +44 91 222 7923]

Flight control computers 'to bypass pilots'
The Independent (a national UK paper), 19 May 93

Christian Wolmar reports on a new electronic system for air communications

While aircraft flown with the aid of computers have transformed the role of
pilots, communications between aircraft and ground control have changed little
since the early days of aviation. "Roger" and his pal "out" still feature
prominently, and misunderstood instructions have led to several of crashes.

All that is set to change. Yesterday the first test demonstration of
equipment which will allow pilots and air traffic controllers to
communicate through computers was held. An experimental BAC 1-11 "flying
laboratory", belonging to the Defence Research Agency at Bedford, flew
above East Anglia sending and receiving messages on its on-board computer.

This project, called the Experimental Flight Management System, is part of a
Europe-wide programme that is expected to enable commercial aircraft to begin
communicating in this way by 1998, saving time and reducing the risk of

Trevor Gilpin, programme manager for the National Air Traffic Services, the
organisation responsible for air traffic control, says the new system has
many advantages: "The airwaves are getting very cluttered and would not be
able to cope with the expected doubling of air traffic over the next 15
years. The system also ensures that no mistakes are made."

Pilots will be able to get weather information on their screens, whereas at
the moment they can only do so by tuning to a special radio frequency.

The messages from ground control can also go direct to the plane's auto
pilot, which raises the possibility, already mooted by the European
aircraft manufacturing consortium Airbus, that pilots may become redundant.
Aircraft could be controlled from the ground with a person in the cockpit
as a failsafe. A ground-based computer could ensure pilots have carried
out its instructions and send a warning if they have failed to do so.

Mr Gilpin feels that there will always be a pilot but accepts that the role
of both pilot and air traffic controller will be different: "They will
control by exception, in other words leaving all routine tasks to be done
automatically by the computers."

At the core of the system is a new form of radar communication, called Mode
S, which allows information to be transmitted electronically. For it to be
used widely, new transmission centres will have to be built throughout
Europe. Mode S allows aircraft to be tracked in four dimensions - including
time - which enables tighter control of airspace, reducing delays. Partial
introduction of the system is expected in 1996.

Electronic information also needs to be sent between air traffic control
centres and already nine, mainly in northern Europe, are able to send
messages to each other's computers. This is reducing delays since
previously air traffic control centres had to telephone each other with
flight plan information.

The urgency of introducing the new system was highlighted last month in a
letter to Flight International in which a pilot said that air
communications between the Far East and Eastern Europe were so bad because
of high demand and old equipment that an accident appeared inevitable. He
said: "If and when an accident does occur, I can imagine the amount of
words which will be spoken and published in the press and official
inquiries wondering how a state of affairs like this has been allowed to
exist for so long."

A long-haul pilot also told the Independent that at times he was unable to
contact ground control when there were bad radio conditions over the
Atlantic "while the guy in the back can phone his wife on a mobile
telephone using satellite links".


Date: Fri, 4 Jun 93 08:37:31 +0100
From: erling@wm.estec.esa.nl (Erling Kristiansen)
Subject: Re: Flight control computers to bypass pilots (RISKS-14.65)

The Independent article says
> Yesterday the first test demonstration of equipment which will allow pilots 
> and air traffic controllers to communicate through computers was held.

It is not quite true that this was the first demonstration of such
capabilities. The European Space Agence (ESA), in cooperation with several
organizations and airlines, demonstrated our PRODAT satellite mobile
communication system with, among other features, ATC digital communication,
starting in 1987.

The trials included installations on several aircraft - including the very
same BAC 1-11 quoted in the Independent article. One Airbus 310 was flying the
equipment for more than a year, and ATC experimenters were collecting flight
data on a regular basis, but the system was not actually part of the ATC
operations of this aircraft. One dedicated flight, with a private Jetstream
aircraft, between Madrid and London, was carried out with the PRODAT link as
primary ATC communication channel (and voice as backup) for the part of the
flight taking place in Spanish airspace.

Admittedly, the scope of the PRODAT trials was more limited than that of the
Mode-S. The goal was to demonstrate the feasibility of digital satellite
communication for ATC (and airline) purposes. All equipment was to prototype
standards, and a possible commercialization would have taken place in a second

The trial system incorporated capabilities for the controller to access flight
data, but no to down (up?)-load data into the aircraft equipment.
Pilot-to-controller messaging was also provided.

The aeronautical part of PRODAT has been discontinued for a variety of reasons
(competing systems, standardization going in other directions). PRODAT still
continues, and is on the verge of commercial deployment for land mobiles - but
that is another story.

The RISK? When the press proclaims a FIRST, do not always believe it.

Erling Kristiansen, ESTEC, European Space Agency, Noordwijk, The Netherlands


Date: Thu, 10 Jun 93 09:18 MDT
From: timothy@tbucks.com
Subject: Re: Flight control computers 'to bypass pilots' (RISKS-14.65)

I would like to address this subject; I am an Air Traffic Controller with 13
years experience in most control functions, including Radar and Oceanic

Most communications with pilots over or near land take place under VHF or UHF
A/G radio. If, for example, I want to descend a flight to FL 240 (24,000 feet)
I say "Flight No., descend and maintain flight level two four zero." The pilot
will acknowledge by repeating his flight number and the assigned altitude,
then begin a descent. (Well, lots of times they will question the altitude but
let's not get into that <g>).

At the same time I'm speaking, I will punch the flight id and altitude into my
computer, and the assigned altitude will be displayed on the scope. But that
bears no relation to what I've said, or the pilot heard or said back to me.

I might be thinking 240, punch 240 into the computer, but say 220. I should
catch the error when the pilot reads back the clearance, but I might not. I
might say 240, but the pilot hears 220, and I don't catch the error on
read-back. He might read back 240, but put 220 into his flight director. Each
of these errors happens from time to time, and can cause problems.

Using Mode S, I would enter the flight id and altitude and that would be sent
to the cockpit, where the pilot would acknowledge by pressing a button. My
display would indicate the acknowledgement. The pilot could still question the
clearance via voice radio.

Mode S would not eliminate errors; I might for example punch in the wrong
flight id or altitude. But it should reduce greatly incidents in which the
pilot is doing something other than what is shown on my display. Since I am
continually scanning that display for potential conflicts, it is vital that it
accurately reflect the intentions of the pilots.

There will, I think, always be a pilot (though perhaps someday only one) but
the pilot in command already leaves many tasks to the computer. A commercial
airliner is on auto-pilot most of the time after take-off, and can begin a
landing approach. The most advanced systems can make a landing in zero
visibility conditions, which a human pilot cannot.

Timothy Buchanan


I recently was on a 737-300 United flight. The pilots gave me a nice demo
of the computerized infomation system. It has all the nice things with
all the SIDs and STARs for airports as well as their flight plan, etc.
The thing that they thought was the neatest was their digital radio 
datalink.  With it they could access the United database while in
flight (and on the ground), and get weather info enroute and at
the destination. They could also do the reporting of maintainence
items that they usually do by voice. I did ask, just to make sure,
whether they still have to dial in the ATIS on arrival. They do, but
you could imagine that, if this system works out, that function may be
the one of the first things switched over entirely to the digital link.

Dennis Ernst