1/18 Following a thread about the work done by @IrishAirCorps helicopters, when looking at a replacement for the AW139, we must look at what we are replacing. It was selected as a winner in a tender competition, the final entrants of which also included the Blackhawk and EC145. https://twitter.com/_IDFOC/status/1376517039083372548

2/18 The UH 60 Blackhawk - shown here with external stores system carrying fuel tanks - was a competitor to the AW139 in that tender process. The Sikorsky offer was that they would put three A models on the ramp more or less straight away while the new ones were being built.

3/18 H145 the other competitor in the AW139 tender would've been a disaster for the @defenceforces if selected at the time, providing a much reduced lift capability. @BerryCathal @GCraughwell @kevpipps @tchukstr @koceallaigh @donlav @kforfitz_Wayne

4/18 It would, however provide a good platform to replace/ reinforce 302 Squadron, allowing the existing H135s to move to a pure Intelligence, Surveillance, and Reconnaissance (ISR) role in a Land Component support role. @RACO_DF @ARCOIreland @slandail_nssi

5/18 That competition recognised the domestic security situation at the time as benign. Roles such as Emergency Aeromedical Service (EAS) and fire fighting were not foreseen, there was no Night Vision Goggle (NVG) capability at the time and the main effort was...

6/18 ...envisaged to be preparing a pre-2012 Re-org Army for overseas missions and air ambulance tasks. The Brexit referendum was a decade away and notions of successful foreign interference in Western elections would have seemed paranoid.

7/18 Syria and Ukraine were both intact countries and the vast movement of refugees across the Mediterranean had not yet occurred. @IRLDeptDefence @IRLCoDF @JohnMinihan @CllrPioSmith @SorcaClarke_TD @MarkWall1

8/18 In that seemingly distant past, the purchase of the AW139 was not entirely inconsistent with reality, although the initial assessment that four airframes (numbers five and six were options on the contract) would be adequate was always overly optimistic. @MccrumJacqui @DFPRB

9/18 Experience has shown that, not only has the operational picture changed, but that the initial maintenance related availability figures were optimistic too. The numbers of machines available each day to fly has not been as high as it was initially promised to be.

10/18 Being able to rely on a fleet of just six aircraft to replace the eight Allouettes and five Dauphins has not entirely worked, some days there’s just not enough machines. @ahernegerald @beaufortcomment @PeterOHalloran1

11/18 The aircraft itself has proven extremely popular worldwide, with the most recent major customer being the USAF. It is a mid-sized machine and with a crew of three, it will also carry around nine fully equipped troops. @ConorGallaghe_r @conormlally @joseph_aidan

12/18 The Air Corps machines weigh in at 6400KG max all up weight and have an endurance of about three hours to tanks dry. They are not fitted with anti-ice protection, which has proven a draw back in Irish conditions. @KeohaneDan @KennethMcDonagh @CharlieFlanagan @lawlessj

13/18 Newer versions of the machine can work up to 7000kg, can be fitted with an auxiliary fuel tank giving an extra hour plus of fuel and are fitted with anti-ice kit. There is also provision for self-defence equipment such as chaff and flare dispensers. @Aiden_Corkery

14/18 Recognising that now is the right time to start considering a replacement, we can use the following timeline as a rough guide: one year to assess all the likely needs of the DF and other users, and to project the concept of ops for the new helicopter fleet. @kourousis_k

15/18 Allow another year plus to really get into the detail of nailing down the specs of the replacement needed to meet that requirement (remember there will be operational, airworthiness and maintainability considerations here) and advertise a tender. @GorseFires @jjsalmo

16/18 Once you have made your decision, it could be up to two years before a machine hits the ramp in Baldonnel, depending on the type chosen. During this time, the AW139 fleet is getting older and ongoing or increasing operational needs must still be met, so you can't...

17/18 ...just send all of 301 Squadron away at once to get to know the new heli. Allow another year at least to get to an Initial Operational Capability (that will have been defined in year one) for the whole squadron, at which point you can stand down your existing fleet.

18/18 As you can see, the process can add up to about five and a half to six years quite easily if any slippage occurs. (With thanks to @declan275 for content).

@SpotterIrish @ConorHogarty @Michaelkelly707 @joshreynolds316 @CormacJOKeeffe