One recollection of mine from many a ground crew perspective. In 1982, during the Falklands, I was sent out to Gib as an aircraft electrician to investigate a Herc whose "hydraulics" weren't working, with the intention of fixing so it could fly back to Lyneham.
After a short investigation, found that a valve had been incorrectly connected whilst on a recent major servicing. Having fixed the wiring and tested OK, we attempted to take off. During the takeoff, I noticed a hydraulic leak in the roof of the cargo bay and after a very short and abrupt conversation with the pilot the takeoff was aborted.
After much scratching of heads and reading of electrical diagrams, I determined that the pipe carrying the hydraulic fluid was only used to bring the undercarriage up and that no fluid would flow through whilst in the air! We spoke with the guys at Lyneham who concurred with my logic and also explained that they thought if they sent out a small team it was still a 6 week job to remove all the wiring, control cables etc etc to get to this pipe.
As the Falklands was in full steam at this time, all aircraft were heading South and no one was interested in picking us up to go to North. As a crew we all agreed we didn't want to stay in Gib for 6 weeks (i would add that i was the only person in Gib in Blue not Khaki and was definitely out of place) and the Pilot asked me to consider any alternatives. Confident ish that we shouldn't loose too much fluid whilst raising the undercarriage, we decided to mark up a large polythene bag in 1 Ltr graduations and tape it over the area of roof where the leak was coming from.
We figured out how much Hydraulic fluid there should be and determined that if we lost less than 20 Ltrs in total we would be fine. So we taxied down and took off, with me standing on a ladder, holding the bag to the roof with one arm, using the other arm to hold on to the cable trays to stop me falling of the ladder and shouting out to the Pilot over a headset how much fluid we had lost!
We lost 5 Ltrs during the raising of the undercarriage and so continued with the flight home. All was quiet on the flight home with no further leakage, but as we approached Lyneham, the adrenalin kicked in again as we rehearsed when and how we would start winding down the undercarriage if we lost too much fluid. Safe to say we landed ok and the Herc subsequently went to Marshalls for almost 3 months to get sorted.