Feb 9 (Reuters) - Singapore Airlines Ltd
* agreed to place firm orders with Boeing for 20 777-9s and 19 787-10s, for additional growth and fleet modernisation through next decade
* Proposed order, is valued at $13.8 bln based on published list prices
* 777-9s are due for delivery from 2021/22 financial year and 787-10s for delivery from 2020/21 financial year.
* SIA has selected Rolls-Royce Trent 1000 to power 787-10s, which are to be operated on medium-range routes
* signs LOI with US airframe manufacturer comprising 39 firm orders plus six options for each aircraft type, if exercised will enlarge deal to as many as 51 aircraft Source text for Eikon: Further company coverage: