A method for predicting the rate and effect of approach to the stall of a microlight aeroplane

The stall and immediately post-stall behaviour of a microlight aeroplane are shown to be a function of the deceleration rate prior to the stall; therefore, it is necessary to use a representative deceleration rate when determining the acceptability of stall and post-stall handling qualities. This research has found means by which the range of deceleration rates likely to be seen in a particular type can be estimated, so that flight test programmes can ensure these rates are included, and thus aircraft are confirmed to have acceptable stalling characteristics. Recommendations are made towards the use of this research for all aircraft type, and of further work which might usefully be carried out

BCAR section S issue 2 - What is possible and a review of existing designs

British Civil Airworthiness Requirements Section S “Small Light Aeroplanes” is a standard based upon the European light aircraft standard JAR-VLA. It is an unusual standard in that it is a UK administered standard that is still in routine use and development, not having been superseded by a Joint Airworthiness Requirement (JAR). Section S applies to the artificially defined class of “Microlight Aircraft” (some of which are also referred to as “SLAs”)

Less weight more fun

Microlight Aviation is still in its infancy, yet in the 20 years since enthusiasts around the world started fitting lawnmower engines to hang-gliders or small makeshift wings progress has been remarkable. Since then, microlight flying has become a mainstream activity in General Aviation; in the United Kingdom alone Microlights are now 21% of civil registrations, outnumbering either gliders or homebuilt light aircraft. The rapid expansion in microlight or ultralight aircraft worldwide has unfortunately not been matched by the development or commonality of regulations. Even the name is not common; the UK, New Zealand and Ireland refer to “Microlights”, France refers to “ULMs” (Ultra Leger Motorise), whilst many other countries have preferred the term “Ultralight”, including the USA and Australia

Pushing the envelope

This article is a description of the manoeuvre envelope in microlight aeroplanes, and how it is determined

A timed method for the estimation of aeroplane take-off and landing distances

This paper describes a method by which, without the use of external personnel or equipment, take-off and landing distances of an aeroplane may be estimated. An error analysis for the method, allowing determination of outcome accuracy, is also shown. The method is validated through use of flight test results from two certification programmes: one on a light aeroplane, and one on a microlight aeroplane

Stalling speeds and determination of manoeuver speed for Rogallo-winged microlight airplanes

Rogallo-winged airplanes can display a non-square law of stall speed versus loading. This Note shows, from experimental data, the form of this relationship and how this has been used during the certification of such airplanes, through operating data and modification of either maneuver speed or the normal acceleration limit

Safety for non-microlight pilots

Microlight aircraft are some of the safest, cheapest and most fun aircraft flying in the UK. The fatal accident rate, at around 1 per 30,000 flying hours is similar to that of General Aviation overall, and rather better than some parts of it in recent years. However, at the BMAA we see several perfectly serviceable aircraft per year written off by very experienced GA pilots, typically with several thousand hours. Why? - well because they are different, not more difficult or more dangerous, just different. The phrase “it’s only a microlight” has as much validity as “it’s only a jet fighter” all aircraft will treat you back as they are treated

Regression approaches for Approximate Bayesian Computation

This book chapter introduces regression approaches and regression adjustment for Approximate Bayesian Computation (ABC). Regression adjustment adjusts parameter values after rejection sampling in order to account for the imperfect match between simulations and observations. Imperfect match between simulations and observations can be more pronounced when there are many summary statistics, a phenomenon coined as the curse of dimensionality. Because of this imperfect match, credibility intervals obtained with regression approaches can be inflated compared to true credibility intervals. The chapter presents the main concepts underlying regression adjustment. A theorem that compares theoretical properties of posterior distributions obtained with and without regression adjustment is presented. Last, a practical application of regression adjustment in population genetics shows that regression adjustment shrinks posterior distributions compared to rejection approaches, which is a solution to avoid inflated credibility intervals.Comment: Book chapter, published in Handbook of Approximate Bayesian Computation 201

Protecting the flight test programme

Considerable effort is put into the safety risk assessment of any flight test programme - and rightly so, since failures to apply best practice in this area may cause significant expense, and in extremis loss of life. However, it must also be remembered that the flight test programme itself is an essential component in the development of the aircraft or system, and that even if safety is never compromised, the failure of a test programme to deliver the required results on time and budget can cause failure of the entire aircraft programme. This paper considers the areas in which planning and conduct of a flight test programme should be protected. In particular it considers the conduct of flight test personnel in ways which go beyond only safety training, the important of documenting all flight test planning and conduct and the continuous justification of flight test conclusions, planning project manning to ensure that the loss (for whatever reason) of key personnel or equipment does not cause complete failure of the flight test programme, how to recover from significant programme disruptions, and most importantly whilst protecting or recovering the flight test programme – how to ensure that safety is not compromised in the process