The Commercial Transport Aircraft Industry, in common with most other industries, is gradually but continually changing its form and methods of operation to match the changing social, economic and technological climates of the world. It must be the concern of those responsible for Airworthiness within the industry to ensure that the present high levels of Airworthiness achieved are maintained and improved despite the changing circumstances.

Airworthiness cannot be achieved by regulation. Regulation can establish a framework within which all who are concerned with the design, construction and operation of aircraft can work, and can set boundaries of responsible behaviour. Within that framework airworthiness can only be achieved by the actions of constructors, operators and authorities, and it is the management of those actions which is the subject of today’s discussions.

What is the record of the airlines over the past two decades? Is it a performance of which we can be proud? Have accidents occurred that could have been avoided? Are we becoming complacent? What may be the consequences of the present airline economic situation with regard to airworthiness? Are our staff adequately trained and will they continue to be so?

These are just a few of the questions we must keep asking ourselves if we are to improve our airworthiness and safety records.

Whilst I doubt my experience is unique, it is a fact of life that I have never enjoyed the sort of back up one expects as a customer who has bought an aircraft from a factory which built it and which contracted to support it.

Starting in 1949 with very much used DC-3’s, then on to ex BEA Vikings and Ambassadors, ex Canadair Argonauts and ex Pan Am DC-4’s and DC-7DF’s, with ex Flying Tiger CL-44’s and ex KLM DC-8’s, the entire story has been one of secondhand hand-me-downs, but with a factory still in operation to which as a several times removed customer, one could always turn to for help. On my acquisition of Carvairs in 1971 when I bought BAF, the same situation applied, and having a much modified obsolete aircraft did not exactly enhance the ease of maintenance.

Airworthiness — fitness for flight — is one of the main factors influencing aircraft design. This joint paper discusses the problems of managing airworthiness and some of the methods used in an aircraft design organisation dealing with new and development designs and ‘in service’ aircraft.

External standards of airworthiness are set by many national and international authorities and it is vital that the aircraft manufacturer plays his part in setting these standards so that the implication on operational economics and production liability are considered. In addition the manufacturer sets his own internal standards of airworthiness. The relationship between civil and military airworthiness requirements are reviewed.

The management of civil aircraft airworthiness must embrace three requirements.

• 1. To establish a working system which ensures that airworthiness is achieved.

• 2. To demonstrate to the certification authorities that it has been achieved and

• 3. To ensure that airworthiness is maintained throughout the life of the aircraft.

The sub-contractor’s task has traditionally been one of carrying out appropriate analysis and testing and then to supply to the prime contractor (usually the aircraft constructor) the data on his equipment which is required to satisfy these three requirements. Subsequently he must support this, as necessary, with the operators until the end of the life of the aircraft.

Airworthiness is not clearly enough defined for its management to be a teaching objective in itself. It is in any case not the principal aim of the aircraft operator but subsidiary to the transport function. Education in the management of air transport engineering is directed towards the process of producing aircraft fit to be used for their economic purpose and the management of airworthiness is inextricably embedded in it.

Nevertheless a number of subject areas which such courses should include can be identified as relevant to current airworthiness problems.

The large number of enquiries received by the BHAB show that there is a need for basic guidelines on this subject. These are given here but more detailed information is available from the Civil Aviation Authority, AS4.

Any owner of a piece of ground may use it as a helicopter landing facility without any kind of permission, provided the following conditions are met:

1. a. It is not in a congested area, as defined in Article 90 of the Air Navigation Order 1976, that is, any area which is substantially used for residential, industrial, commercial or recreational purposes.

   (Note: In this context, the CAA considers the term “substantial’ to mean 50% or more.)

2. b. No structure is erected in connection with its use as a helicopter landing area, eg concrete landing pad, hangar,etc, other than a temporary structure such as a windsock.

3. c. Its usage is confined to the private or business use of the owner, his employees or anyone specifically visiting him for social or business purposes.

4. d. A pilot using the site will be able to conform with Rule 5 of the Rules of the Air and Air Traffic Control Regulations 1976.

There seems to be a preconceived notion amongst an element of urban society that a heliport in its midst can contribute nothing worthwhile to it. The uneducated conjure fears of noise, added road congestion and hazard to both person and property. The prejudiced choose to think in terms of pandering to the privileged. In reality the effect of a heliport upon its urban environment, once the dust of cautious suspicion has settled, is likely to be unnoticeable by all but a very few persons. Noise levels need not be onerous, demands on roads and real estate are likely to be minimal whilst safety may remain fundamentally inviolate.

A heliport criteria exclusively for major metropolitan heliports was developed by the International Air Transport Association (IATA) as far back as 1955 and was developed to provide guidance to the helicopter operator and to those concerned with the planning, construction and regulation and operation of heliports. It is interesting to note that although at that time there had been no operating experience with either turbine powered helicopters or multi-engined helicopters this criteria has remained in broad outlines very similar over the years. It is however, sad to relate that some 27 years after this IATA criteria was drafted we still do not have a full IFR Metropolitan heliport as then envisaged. I hope to examine some of the reasons for this and to review the current prospects and requirements for a full IFR heliport.

In this paper, the second of two associated papers on IFR heliports, the requirements outlined in the first paper by Mr. F. W. Free for electronic approach aids are examined in more detail and the current status of technical development reviewed.

If the necessary reliability of service to the heliport is to be maintained under adverse weather conditions, then some form of electronic approach and landing system will be required in order to satisfy the stringent safety requirements set by the CAA and in particular, the obstacle clearance criteria in an urban environment. In addition, the provision of an approach aid may give benefits in noise abatement arising from an accurately controlled flight profile even in adverse weather conditions.

The helicopter has the ability to operate from small spaces. Its ability to hover and fly slowly efficiently allows it to perform tasks such as surveillance and rescue even in an urban environment. It is however its ability to provide a form of transport into urban communities where surface transport is restricted by the number of routes and/or congestion, as well as to smaller but less readily reached locations that attracts much attention. The development of cost effective helicopters, as well as commercial helicopters with a larger payload indicate that the world is entering another phase in VTOL travel. It is therefore natural that one should consider the environmental factors in such operations.

The role of the Civil Aviation Authority in urban heliports, as with most other activities with which it is concerned, can effectively be summed up in one word — SAFETY. We are concerned, not only with safety of the helicopter crew and passengers, but also with third parties and property and, where relevant, other users of controlled or special rules airspace.

Unfortunately, like most other things, safety can only be achieved at a price and the price to pay is often at variance with commercial interests, private operators’ resources and even with the basic concept of helicopter operation. The Authority, by consultation has aimed at achieving an effective compromise by a flexible application of the criteria where it is safe to do so.

This paper is presented in relation to a medium sized coastal town in an English shire county.

The statutory functions of local planning authorities in England and Wales were consolidated in the Town & Country Planning Act, 1971 as amended by the Act of 1972. The general planning controls which are embodied in current legislation provide a framework for the submission of planning applications and their determination by local authorities.

Local Planning Authorities, and particularly District Councils, are empowered to determine a wide range of formal applications which relate to land within their own boundaries. The boundary of most coastal authorities stops at low water although there are exceptions, particularly in tidal estuaries.

The present note is concerned with the bending of a thin polar orthotropic circular plate having mixed boundary conditions. Problems of this type have been rather sparingly treated in the literature and all of these deal with isotropic plates having idealised classical boundary conditions. In practice, plate elements of structures do not have ideal edge supports, but are in general, restrained elastically from rotation and translation at the boundaries. Also, the plate might have non-uniform support conditions. The case of polar orthotropic plates with realistic boundary supports appears not to have been investigated so far. Only a few cases involving the bending of plates of this type have been reported in the literature and these too are for ideal boundary conditions.