The Nimrod Review - Official Documents

The Nimrod Review
9.35
9.36
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aircraft”, 52 adopting the HSC’s definition of a Safety Case as “A suite of documents providing a written
demonstration that risks have been reduced as low as reasonably practicable. It is intended to be a living
dossier which underpins every safety-related decision made by the licensee”. JSP318B further provided that: (1)
the Safety Case should clearly describe the evidence and arguments used to justify the safety of the system; 53
and (2) that it was the responsibility of the IPT leader (IPTL) to ensure that the Safety Case was supported by a
safety analysis in accordance with Def-Stan 00-56 (see further below) 54 and that it was independently assessed,
in order to “overcome possible conflicts of interest and oversights that may arise from the use of a single
organisation”. 55 Such independent assessment was to consist of two elements: audit against the safety plan and
technical evaluation of the Safety Case and supporting analyses. 56
Chapter 4 of JSP318B dealt with the “Management of Airworthiness During Procurement”. Despite its title,
paragraph 4.50 prescribed that IPTLs of projects involving legacy aircraft and equipment that did not already
have a Safety Case were to undertake as much of the analysis prescribed in JSP318B as was “reasonably
practicable given the available safety records”. Further guidance on the safety analysis of legacy systems was
said to be contained in Def-Stan 00-56, Part 2, Annex D, discussed below.
th In 2003, JSP318B, 4 Edition (as amended) was re-published, renamed JSP553 “Military Airworthiness
Regulations” and incorporated into the JSP550 series of publications forming the Military Aviation Regulations
Document Set (MARDS). The substance of the regulations in relation to Safety Cases remained unchanged.
Def-Stan 00-56
9.37
Defence Standards are used by the MOD as contractual requirements with Industry.
Issue 1 of Def-Stan 00-56
9.38
57 Def-Stan 00-56 Interim Issue 1 was published by the MOD on 5 April 1991 to give the MOD a consistent
approach to the contracting of Safety Management requirements. It was, however, primarily focused on
computer based systems. As referred to above, the Man S (Org) Study recommended the development of Def-
Stan 00-56 to address the whole safety system.
Issue 2 of Def-Stan 00-56
9.39
Issue 2 of Def-Stan 00-56 entitled “Safety Management Requirements for Defence Systems” was duly published
on 13 December 1996. It provided “uniform requirements for implementing a system safety programme in
order to identify hazards and to impose design techniques and management controls to identify, evaluate and
reduce their associated risks to a tolerable level”. 58 These requirements were set out in some considerable detail
in the Def-Stan. In particular:
9.39.1 Paragraph 4.6 provided for a Hazard Log to be established to act as a directory for the safety justification,
or Safety Case, and to provide a summary of all safety activities throughout the project life. The Hazard
Log was to be employed as the principal means of establishing progress on resolving the risks associated
with the identified hazards.
9.39.2 Paragraph 4.7 stated that the Hazard Log alone was unlikely to be acceptable as a Safety Case, which
was to be constructed using information from the Hazard Log. The Safety Case was to provide a wellorganised
and reasoned justification clearly showing that the proposed system was acceptably safe.
52 Ibid, ntroduction, paragraph 9 and Chapter 2, paragraph 2.43.
53 Ibid, Chapter 2, paragraph 2.45.
54 Ibid, Chapter 2, paragraph 2.56.
55 Ibid, Chapter 2, paragraphs 2.47 and 2.58.
56 Ibid, Chapter 2, paragraph 2.59.
57 Entitled “Hazard Analysis and Safety Classification of the Computer and Programmable Electronic System Elements of Defence Equipment”.
58 Def-Stan 00-56 (Part 1)/Issue 2, paragraph 0.2.