As a B1 LAE you can certify any task listed in the aircraft maintenance manual or structure repair manual. You can also certify work if the aircraft manufacturer or design authority for the aircraft supplies a work pack, dependent on tooling being available. To replace a spar for example, if the task is not listed in the SRM you could request a repair from the design authority or manufacturer. You'd need the same approval to manufacture a part.
Hangar or line has no bearing on this. An LAE is an LAE and a repair can be carried out anywhere that has suitable facilities. For example, a few years ago an RJ100 was damaged during landing at London City. It was stuck on a barge, transferred to old docks and repaired there.
VIDEO and PICTURES: Swiss has removed damaged Avro RJ100 on floating pontoon at London City