A storm of criticism has followed publication of the US John Hopkins University (JHU) report on future navigation systems, particularly Global Positioning System (GPS) satellite navigation.

The University concluded that GPS could be a safe "sole means" guidance system, including for precision approaches (Flight International, 10-16 February). Experts have said the study is flawed partly because when the US Federal Aviation Administration commissioned it, the wrong questions were asked.

The criticisms follow the established line that GPS is too vulnerable to failures or interference that could affect wide areas and many airports simultaneously. There was also agreement that the university had been given the wrong terms of reference and additionally that its conclusions had been "hesitant".

International Federation of Airline Pilots' Associations(IFALPA) Capt Peter Foreman says: "I think that, if the academics had been asked: 'Should we make [augmented] GPS -the sole means of navigation and turn off all other navigation aids,' the answer might have been different. The question then becomes not what is possible or can be justified, but what is the wisest course of action."

Foreman is chairman of IFALPA's air traffic services committee, a member of the International Civil Aviation Organisation (ICAO) Air Traffic Management Concept Panel, and director of the worldwide Air Traffic Control Association.

Sieg Poritzky, the US chief representative on the ICAO Future Air Navigation System committee, having described the main conclusions as "hesitant", also maintains that John Hopkins was given the wrong terms of reference.

Source: Flight International