A twin engined utility helicopter manufactured by Aerospatiale in France.  There is seating capacity for up to three passengers.  These aircraft replaced the single engined Gazelles, allowing for more greater performance and flexible use in all weather conditions, as well as the ability to fly the London Helicopter routes at night.
 

Serial	Model	C/No	Delivered	Notes
ZJ139	AS355F1 Ecureil	5325	30/03/96	see below
ZJ140	AS355F1 Ecureil	5303	30/03/96	see below
ZH141	AS355F1 Ecureil	5327	----------	see below
G-BXBT	AS355F1 Ecureil	5262	---------	see below

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These helicopters were originally supplied under a three year contract with Operational Support Services / McAlpine Helicopters, which expired on 31st March 1999 when the contract was up for renewal.  Part of the attraction of the  contract was that a civil registered aircraft could be substituted at short notice in case of one of the based aircraft being unavailable.  The military serialled helicopters were delivered to Northolt on 30th March 1996 as 'RRR711' & 'RRR712' respectively, and an intensive weekend of familiarisation immediately took place.  They are crewed by RAF pilots but maintenance is performed by OSS at their own facilities.
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The complement was increased to three the end of May 1998 with the addition of a civil registered example, also from OSS. The new aircraft was rotated between G-BXBT and G-OILX, which had regularly been used to replace the original examples when they were unavailable due to maintenence etc.
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G-OILX was later re-registered as ZH141 and was first noted as such on 25th February 1999.  Registration G-OILX was similtaneosly cancelled from the UK Civil  register as 'sold to the MOD'.  The aircraft had been operating from Northolt for some time, in an  overall dark blue colour scheme.  This event confirmed the extension of the OSS contract.  The serial is a surprise, being the use  of an unused serial allocated some years ago. The aircraft was later repainted into the standard 32sqn  scheme.  Life in this guise ended on 6th February 2006  when it was re-registered as G-OILX to Premiar Aviation Services in preparation for the arrival of the Agusta A109's.  As of the end of December 2005 the aircraft had flown 4,902 hours, having been built in 1985.
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ZH141 on the north side pan, with inset to illustrate the small serial above where G-OILX was painted over