Representatives of the world's air transport industry attended an important colloquium organized by ICAO at its Montreal headquarters in early April. A report on the outcome of the ICAO Colloquium begins on page 7.

The airline industry encountered both higher costs and declining traffic in 1991. A review of developments and industry performance begins on page 11. According to an ICAO study, the medium term outlook for the industry looks more promising.

Several environmental issues are of concern to the civil aviation community, ranging from long-standing issues such as aircraft noise, to new concerns over global environmental problems.

In the past few years Finland has replaced all of its conventional VHF omnidirectional radio range (VOR) stations with Doppler VORs. As part of its modernization of air navigation services, the Civil Aviation Administration is proceeding with the Finnish Air Traffic Management Integration (FATMI) Programme.

An artist's depiction presents an orbital view of satellites of the SARSAT (top) and COSPAS systems. Designed to pinpoint the source of distress signals emitted by emergency locator beacons, the satellites have proved effective in expediting search and rescue (SAR) operations. An article on SAR technology begins on page 12.

Delegations from most of the Contracting States of ICAO and from observing organizations gathered at ICAO Headquarters in Montreal for the recent 29th Assembly. Symbolic of ICAO's role in the development of international civil aviation is the large bronze emblem mounted in the Council Chamber. (A larger emblem is also mounted in the Assembly Hall.) The sculptural reliefs were donated by the Government of the former USSR.

Mount Pinatubo in the Philippines is shown smouldering in late June 1991 in this photograph taken by the U.S. Geological Survey. Although predicting the dispersion of volcanic ash doud and other harmful atmospheric material can be difficult, a computer simulation model has produced impressive results.

The image illustrates flight tracks in the vicinity of Sydney (Kingsford Smith) Airport, Australia.

A turn-of-the-century commercial tiltrotor aircraft could extend the useful life of existing airports and preserve service from small airports to congested hubs, according to a recent study. A brief analysis of the technical changes required to develop a civil tiltrotor based on the existing V-22 Osprey begins on page 6.

Artist's illustration of a global positioning system (GPS) satellite. The GPS satellite constellation will eventually consist of 21 satellites, plus three spares. A team of engineers from the United States and the Soviet Union are currently evaluating integration of the USSR's satellite navigation system and the U.S.-launched GPS.

Lightning can be very hazardous to your health. Early detection in flight of the presence of thunderstorms can make a difference. For details on one such airborne early warning system, see story beginning on page 16.

Because of the great advances in computer technology in recent years, flight simulator visual systems have steadily improved and yet they have continued to be affordable. New features such as photo-texture hi-linear blending and enhanced system capacity are found in the advanced equipment being produced by Rediffusion Simulation in the United Kingdom. Shown is a view of a new MD-11 flight simulator employing the firm's SP-X 500 visual system.