Orb expertise needed.

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13 years 5 months

Posts: 552

Orb expertise needed. Can anyone tell me what the "X" numbers mean that are allocated to each aircraft and crew of this orb? Individual radio call signs perhaps?
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Original post

Member for

13 years 5 months

Posts: 552

Bumping this one up again in the hope someone can answer my query. Thanks, David

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19 years 9 months

Posts: 855

Movement Serial Indicator issued by the Movement Liaison Section. Used to classify RDF plots. Ross

Member for

13 years 5 months

Posts: 552

Thanks Ross. Could you please explain that in layman's terms.

Member for

19 years 9 months

Posts: 855

What it says on the tin. If you wanted to move an aircraft by air in wartime before you took off you applied to the Movement Liaison Section for a Movement Serial Indicator and to tell them your route with approximate timings. The MLS gave you next available serial from a letter/number sequence and recorded your details on a list which was sent to all filter rooms. When the aircraft was picked up on RDF/Radar/Observer Corps and reported as unknown to filter room the duty Movement Liaison Officer looked up his list for who was authorised to be there and said either "friendly MSI - disregard" or "hostile - engage". Ross

Member for

13 years 5 months

Posts: 552

Thanks Ross.
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14 years 6 months

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That was very interesting and informative, thanks.