Is napping a good idea? I have just learned that "napping" (controlled rest for flightcrews) while long-haul pilots are seated at the controls is being experimented, or accepted, by some airlines. These airlines apparently have been authorised to implement, or given permission to experiment, such a policy by their respective civil aviation authorities. The recently publicised "napping" benefits to people while at their workplace surely cannot be applied to cockpit crew members. It certainly cannot be applied to workforce involved in a production line. As a retired airline captain I remember that I was taught that a two-pilot crew required continuous awareness, reciprocal cross checking and mandatory acknowledging of inputs. It is obvious that for economic reasons, this "napping" policy is earnestly  accepted and introduced by airlines as to spare the requirement of an augmented cockpit crew (relief pilot) for flights where the planned flight time is very close to the legal maximum. Is it wise? It has been amply proved that air transport is the safest ways of moving around the globe so why not keep it that way for as long as we can? Orlando Giacich Weston super Mare, Somerset, UK

How safe are military twins? There is a continuing debate about the appropriate number of engines for different categories of aircraft.  Recently, this has centred on civil operations, without drawing parallels with the military, which has experience in more marginal conditions and with higher demands on machinery. One of the arguments used by the US Navy to justify the development of the Boeing F/A-18 was that its twin engines would confer greater safety in over-water operation.  On the other hand, the UK Ministry of Defence has had a policy for 30 years of operating single-engined combat aircraft over the sea, and twin-engined aircraft over land. This policy has been so successful, apparently, that not only will it be extended for another 30 years, but the future shipborne fighter, the Lockheed Martin F-35B, will have all the complexity of a twin, but none of the redundancy. Aircraft limping home on half power are not very newsworthy, in peace or in war, so it would be interesting to know how the Jaguar, Tornado, Typhoon, Alpha Jet etc compare with their single-engined contemporaries.  What is the comparative tolerance to bird-strikes, mechanical failure and hostile action? Richard Lloyd Coventry, West Midlands, UK

Taiwan: not a US obligation I write in response to Luke Colton's China Crisis article (Flight International, 5-11 April). There is an important error that needs correcting. You say: "Because the USA is legally obligated to defend Taiwan in the event of a conflict with China." This statement is not true.  Before 1979 the USA had formal relations with the Republic of China (Taiwan) and a security agreement, but in 1979 President Jimmy Carter broke relations with Taiwan and established formal relations with the People's Republic of China. In the same year, Congress passed the Taiwan Relations Act, which allows the USA to provide weapons of a defensive nature to Taiwan, and if Taiwan's security is threatened, the US president and Congress will determine an appropriate course of action. None of this in any way obligates the USA to defend Taiwan if attacked by China.  Kent Harris USA

Evacuation: the right blend? I too was surprised when I saw the make-up of the evacuation evaluation personnel that Airbus intends using for the A380 evacuation certification and agree with Nathan Fruchter's view (Flight International, 5-11 April). Certification agencies should insist on a more representative cross section of the travelling public for these tests and not just use young people and airline staff. Airbus is complying with the letter of the law, but not the spirit Charles Smith Muscat, Oman

Can training be combined? I'm 19, I am tired of education and I want to learn to fly. But I have a problem. To get a fairly secure job these days you need to go to university, so I have applied for aeronautical engineering. However, I am desperate to learn to fly as soon as possible and as getting a private pilot's licence costs up to £5,000 ($9,400) it looks like I am going to have to wait until I graduate to get a job and pay off all of my student loans – and that could be up to six years away. What I want to know is why there isn't a course that teaches you how to fly and includes an engineering degree – surely they go hand on hand? It would benefit everybody. For example, there is a chance that pilots who fail their medical, but have an engineering degree, could be redeployed. I appreciate that it would take longer to learn to fly and get a degree, but in the long term wouldn't it be worth it? Casper MacCormack Oxford, UK

Source: Flight International