Engineering company Smiths Group said its headline operating profit for the full-year was likely to be 15m pounds below current expectations, reflecting contractual issues in its Detection unit. Smiths Detection's headline operating margin has been affected by contract mix and the initial under-recovery of overheads at new manufacturing sites, according to a trading update on Wednesday.The unit has identified that the final outcome of three contractual commitments entered into prior to 2010 are anticipated to be materially adverse to previous expectations.It has also determined to make additional provisions for the costs associated with certain legal disputes. Apart from the Detection unit, trading for all other divisions have continued in line with expectations. The results for the financial year to end of July will be announced on September 18th.RD