Checking In

摘要

In Creating connections (April 2021), you mentioned Inmarsat GX1-GX4 being Boeing (ex-Hughes) 702HP satellites. GX5,I am pleased to point out, is a French Aerospatiale (now Thales Alenia Space) Spacebus 4000B2 built in Cannes.Canada's HeliJet, featured in the May issue of AIR International', is not the longest operating helicopter airline. Heli Air Monaco, for example,has been using AS 350Bs on Cote d'Azur flights since 1980, with 3A-MAG registered on January 17, 1980.Philippe Jung, Grasse I am not enthusiastic about hydrogen as aircraft fuel, and having read 'Together in Electric Dreams' (March 2021), I want to explain why.Firstly, hydrogen must be carried either as gas at very high pressure or in liquid form. As a student of automotive engineering, I had the opportunity to drive a fuel cell-powered Ford van. The hydrogen used as fuel was carried in propeny designed cylinders at 5,000 pounds per square inch [psi]. There was talk at that time of pressures as high as 10,000 psi to pack in enough hydrogen to provide sufficient range. Such pressures make me nervous.