which minor problems can abort a takeoff?
 

I was recently on a two-hour domestic flight from BTH to JOG in Indonesia. About midway thru, I went to use the head to relieve my bladder. I heard a weird noise before opening the door.

Upon entering, I immediately realized that the flush button of the toilet was stuck in open position, creating a vacuum cleaner type whooshing sound. I tossed a tissue into the toilet and it disappeared with frightening speed.

I pushed the flush button but it wouldn't unjam. Alerted FA after doing my business and returned to my seat.

It's possible the flush was broken/stuck open (affecting cabin pressure indirectly) before the plane took off. Would that be reason to return to terminal for repair?

Any other seemingly minor problems that can abort a take-off?

I don't think the amount of air dumping through the flush system would impact pressurization.

In general terms engine, fuel, hydraulic, bleed air, electrics and such malfunctions may lead to an aborted takeoff. Performed properly it's no big deal.

When I think back over some 30+ years of flying the most common problem that has caused delays, and a few full cancellations, have been faulty sensors. Others have been main and cargo doors not securing properly, bad tires, burnt out navigation lights, and at least one bad backup flight computer. Generally speaking I don't question or complain about a captain deciding they won't or can't fly because of an issue.

In hopes of keeping this relevant thread to the rules of the forum - a practical travel/safety tip would be to not sit down on a lavatory with such rampant and crazy suction that it makes things disappear with frightening speed.

YMMV.

:)

More likely is the flush mechanism broke when the person before you used the lavatory. If it happened on the ground before departure they would likely have maintenance either fix it if possible, or disable it and log it out of service if parts aren't available at the departure airport. It would likely cause a delay for maintenance personnel to investigate and complete paperwork, but unlikely to put the whole airplane out of service and cancel the flight.

Maybe I'm reading the OP's post to literally but "abort a takeoff" to me means exactly that, to stop the takeoff once starting down the runway. Using that as a filter changes things considerably.

Depending on the countries, each airline should have a minimum equipment checklist that permits the operation.

As stupid as it sounds, a lav problem can and could result in an aborted take-off when deemed necessary.

Sure can. A small electrical motor that won't shut off goes from a minor annoyance to a major emergency when it overheats and catches fire.

Not sure if the OP meant actual aborting of a takeoff, or he is talking about what sort of minor issues would cause a flight to be delayed until an issue is resolved.

Assuming it's the latter, even minor mechanical issues can result in flight delays. In one case on UA, it was a door on a galley cart (!). And this is on a flight from HKG-EWR which made an unusual stop in SFO to take on new crew (crew rest issues due to flight delayed by typhoon). So a cart door broke somewhere between HKG and SFO, the extra stop in SFO happened, and then we waited 3 hours for them to find the part to fix. And they couldn't find the part, so then they had to get special dispensation to take off with this issue. Said dispensation took another hour, so the flight already delayed 15 hours, plus extended by 3 hours to make an extra stop, now was delayed another 4 hours.
I've seen a broken light on the exit path lighting delay a flight (probably not a bad idea, it's safety equipment) but also far more minor issues such as a broken coffee machine. I always thought the right thing to do is for the captain to say "folks ... we have a broken coffee machine. Should we wait to fix or take off with only 3 working coffee machines." I would imagine the vote would come in positive, and then anyone disagreeing could deplane an take a later flight.
A flight in India where a mouse was running around the plane -- they had to deplane everyone, catch the mouse, and disinfect the plane.
Toilet issues are fairly common causes of flight delays.

No, it wouldn't. A rejected (aborted) takeoff is literally just that - something happens after beginning the takeoff roll but normally before reaching rotation speed. That's a period of usually around 30-60 seconds for the typical airliner and in any case, a time when all passengers and crew are seated with belts fastened. A lav valve mechanism that becomes broken during takeoff would never be observed by anyone, much less result in a rejected takeoff even if it were noticed.

The minimum equipment list (MEL) usually doesn't apply either once takeoff power is applied or once the aircraft begins taxi under its own power, depending on applicable jurisdiction. Not every problem or failure will result in a rejected takeoff. Basically, the focus is only critical things impacting aircraft control, configuration, etc. to enable a safe takeoff.

There is also a misunderstanding about the proverbial broken coffee pot and similar minor things delaying takeoff. Using the coffee pot example, the MEL may state that it's OK to operate the flight but that it has to be disabled and placarded as such. The delay is in having maintenance disable and placard the coffee pot, not that the coffee pot must be replaced or made operational. This isn't to say that some small parts or components on the aircraft may not prevent operation of the flight without being fixed or replaced outright, just using that example as something that doesn't need to go to that point.

I see that "abort" was too technical a term and "take off" is too narrow a time frame. I meant that the plane would return to the terminal after pushing back. Alternatively, could an apparently small problem discovered after takeoff cause a divert to a nearby airport to land and fix it?

In general terms the aircraft's airworthiness is the primary factor in determining to fly or not fly. However, in passenger airplanes other factors come into play such as lavatories and other systems that can impact the comfort and safety of passengers. Part of that decision process would be understanding how the flight will be conducted, i.e., length, and such. Thinking along the lines of "can I fly in this condition" and taking all factors into consideration as to how a problem will impact the flight will determine if the plane goes back to the gate, lands at an alternate airport, or continues to destination.

I'm not sure there is a cut and dried answer to your question.