Select Committee on Public Accounts Minutes of Evidence


Supplementary memorandum submitted by Sir Kevin Tebbit KCB CMG, Permanent Under-Secretary of State, Ministry of Defence

Question 33: Did the Department take that [the stipulated thermally-stable plastic tubes] out of the specification when the order was placed?

  The thermally stable plastic tubes referred to relate to the plastic tubes that make up the main body of the "Main Engine Air Cleaner Cyclone". Each AS90 has one Cyclone. These tubes are still present and were not removed at any time from either the design specification or the AS90. The Cyclone was "thermally stable" for A2 conditions (ie temperatures below 44C). Although the environmental conditions on Exercise SAIF SAREEA were not anticipated to be any higher than A2, actual temperatures reached A1 conditions (ie 49C) and higher.

  The Department is currently working with the AS90 Design Authority (BAE SYSTEMS) on a desertisation kit that will enhance AS90's performance in A1 conditions. One particular area for this enhancement relates to the Cyclone with manufacture of the Cyclone's `plastic tubes' from a more thermally stable material. The Design Authority have now identified a replacement material that will meet the requirements for operating in A1 conditions.

Questions 169-176 and 211-214: Do you have a contractual relationship with them [PALL Aerospace]? Have you considered whether they are in breach of contract [regarding the Challenger 2 filters]? Do we have any indication whether they would meet the 14 hours were that the specified minimum performance if you had the correct skirts and seals fitted to the tank?

  The contract for Challenger 2 filters with PALL Aerospace was for a part number specified by the Challenger 2 Design Authority, Alvis-Vickers Ltd. The Department makes purchases as and when extra stocks are needed ie `x' quantity of the part number `y'. This is similar to the way in which the ordinary consumer buys spare parts for a car; it is not a contract for a special purchase.

  The life expectancy of the air filters is laid down in a British Standard (BS)—BS1701. This British Standard gives a life expectancy of 14 hours (a battlefield day) in zero visibility conditions: that is 1.412 gm/m3 of dust concentration. The CR2 filters meet this requirement. The filters did not perform poorly—rather, they were used in conditions that exceeded the British Standard definition for zero visibility, and therefore, beyond those for which they were originally designed. However, they performed tolerably under these conditions, albeit at a higher rate of usage. Under the circumstances, the Department does not consider it would be appropriate to seek redress of the contractor.

  On the question of whether the filters would have met the 14 hour standard had the tanks been desertised and fitted with features such as side skirts and seals, it is not yet possible to give more than a general assurance. But when the data from work carried out to trial various desertisation options has been fully analysed, the Department should be in position to offer a more precise view on the likely improvements to be gained from fitting skirts and seals.

Question 230: When was it [the contract for the Container Handling Rough Terrain (CHRT) system] signed?

  CHRT came into service in late 1997 and is made by SiSu in Sweden. SiSu and Kalmar are part of the same organisation and for the last four years the 13 CHRT currently in service have been under warranty to Kalmar. This warranty has now expired and the Department set up an enabling contract for specific or specialist repair with Kalmar last month (October 02).

  The Royal Electrical and Mechanical Engineers (REME) provide day to day repairs and general maintenance for CHRT at Unit level. Where more substantial or specialist repair is required this is then passed to the Army Base Repair Organisation (ABRO) who contract out as necessary within the UK or Germany. This is the same repair chain that operates for the majority of vehicles or equipment assemblies.

Question 297: I suppose it is a trade-off as to advantages and benefits [of the new polyester combat outfit given that airlines were advising passengers to wear natural fibres to minimise the risk of injury from aircraft fires]?

  Fabrics made from 100 per cent cotton, 35 per cent polyester/65 per cent cotton mix, or 65 per cent polyester/35 per cent cotton mix will all burn at roughly the same rate. The speed with which these burn depends on the degree of heat applied and the thickness of the cloth. Polycottons (fabrics containing a mix of polyester and cotton) are widely used for both civilian leisure/workwear and military clothing because of their comfort and durability and they pose no greater or lesser a flammability risk than clothing made from 100 per cent cotton.

  Apart from flame being applied to bare skin, burns are caused by the penetration of radiant heat through clothing to the skin and the severity of the burn will depend on the temperature of the heat challenge and its duration. Protection for a short period (measured in seconds, not minutes) can only be gained by providing some form of insulation either by wearing thicker clothing or, better still, multiple layers that also provide additional insulation in the form of air gaps. Flame Retardant (FR) coatings work by forming a charred surface on the fabric which itself becomes more difficult to burn. FR coatings do not provide any protection against radiant heat. The latent heat of fusion of polyester (the heat released as it melts and then solidifies) is not sufficient to increase burn injury significantly. Medical personnel with experience of burns treatment in operations do not support the view that the melt of synthetics onto skin significantly complicates medical treatment. Burns involving synthetic material result in a `cleaner' wound than those involving natural fibres.

  Operational Analysis has shown that the soldier on the battlefield faces a minimal risk from purely burn injuries, the principal damage being from blast and fragmentation. As mentioned above, protection from burns can be gained through greater insulation but this will decrease mobility, increase the physiological load and, when wet, the soldier may face a greater danger from cold injury as his/her clothing dries using body heat. FR coated clothing can be more uncomfortable to wear because the coating tends to stiffen the cloth but it will not protect from radiant heat. A Defence Clothing programme into flame/fire hazard carried out by Porton Down three years ago recommended that material of up to 70 per cent synthetic content could be used in operational clothing worn by Land Forces.

Sir Kevin Tebbit, KCB, CMG

Permanent Under-Secretary of State

Ministry of Defence

November 2002

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Prepared 9 December 2002