I have encountered moderate icing on approach into ZRH. Some parts of my aircraft are not equipped with anti icing devices (particularly the tail). On stand the ice was still solidly attached, but being April and well above 0 the deicing teams where not ready. Took a while to melt off, duty free too expensive to get any vodka ;)

Oh alright then, I raise you the scenario of having to wait for cold soaked wings to de-ice ……in Bermuda of all places…

And yes the decision was made to give an honest explanation…

Totally irrelevant what the departure point temperature was. Temperature reduction with altitude is approximately 2C/1000’. So, at 6,000’ cruise on your “short sector” (unlikely cruise altitude, by the way), the OAT would be 0C and very likely to be in the moderate/severe icing range if flying in cloud.

Someone didn’t do physics at school nor understand the effect of speed and it’s affect on airframe temperatures.

Sometimes the reason for the delay is obvious to everyone. Years ago i was sat on a 757 doing a short domestic flight in the usa and that particular aircraft had been brought over from maintenance to replace the original aircraft which had gone tech earlier. There was a passenger in an overwing exit seat who was having a seatbelt issue, namely it was stuck in the overwing exit. Along came tech person who removed the exit and managed to deploy the slide. From the flight deck came a rather resigned crew member saying basically that the slide would take 4 hours to repack so please gather your belongings and leave the aircraft.

I have been very fortunate. My only other long delay was a simple one. CPT in February 2019 a venerable BA Queen of the Skies.
All aboard and doors shut.
After nearly an hour, my seat mate observes that they will soon push us off stand to beat the (then in force) EU261. But we did not move.

I was sitting in WT+ on the Starboard side, so just above the front cargo door. I saw the Loader arrive and the door opened. I wondered if there was a technical bay they might need to access ... but when the second ULD came out, I turned to my seat mate and said, "This is now an ex-flight". A few minutes later the Captain told us that we were canx as a particular sensor on one engine was no longer sensing anything and the spare was in JNB. Given flight limitation hours, then it was a full 24 hours. Although he did not mention the flight hours limit, just the main delay.

The shift to hotels was badly managed by their local agent but all other respects were good. With EU261 for a nearly full 744, BA must be glad to see the end of that!

So an extra sunny day in CPT with good food and wine and back to the machine after her engine test. The cabin crew member remembered our conversation about food from the previous evening! Such fine service.

Although the Pandemic was clearly established, little did I know that it would be my last on a BA Queen. She just always felt so secure and, despite all the shaking on the take off roll and the old noises, she gave us a beautiful ride home.

Was delayed on EZY from TLV to MAN about three years ago as the incoming aircraft had not arrived. Ground crew had no idea what the reason was. As it happens the flight had to drop down into Sofia for a medical emergency and I knew this as a friend was on the incoming flight and was giving us a blow by blow account via Facebook. The staff were bemused when I told them what was going on and suggested that we get HOTAC sooner rather than later. Remarkably they listened and after some communication with EZY we were removed from the departure lounge, collected our luggage and went off for a nights enforced holiday.

I'm enjoying this thread, having been frustrated by 'Operational Reasons' in the past. In my previous life a more useful pa would help me replan my day as I usually had appointments after my short flights. Flybe were generally quite good, one of the better ones being the copilot called in sick, a standby is in his car driving up from Birmingham (to Doncaster). At least we had a rough timeline.

My longest delay was in Dublin following a storm. I knew it was going to be bad - BA had canceled a lot of their morning flight, whereas Aer Lingus had not, and then when planes were not getting into Dublin ended up with planes and crew well out of position. The flight was due to depart mid-afternoon, and changed gates 9 times. Eventually, there were only two flights left, Manchester and Gran Canaria. We got lucky - Gran Canaria got cancelled and I still wonder where they found hotel rooms.

They called boarding at 23:45, and took out applause in good grace, but did point out we were not the first of the day... We then had to wait a bit for pilots (who thought they were off to Gran Canaria), and even longer for baggage loaders. We arrived into Manchester at 1;30, a long time after my last train home. Manchester had suffered from the same storms and hotels were not available. I ended up in a £150 Uber to Doncaster, which Aer Lingus reimbursed.

Fun times, that I don't expect to experience again.