Your first FAA link says that these 'fume events' are rare: "The report found that the rate of cabin air quality events is less than 33 events per million aircraft departures." This is about one event every 30,000 flights.
it happened to me only on certain planes or cheaper airlines and i never managed to correlate it enough to plane, situation or airline.
the smell is very pungent and scratches the throats, typical fulel /exhaust like.
I learned about the air system passing through the motor because of the safety incident case, where the safety for engine malfunctioned and junctioned high temperature engine oil into the air system when triggered, causing cabin and pilot problems breathing and visibility.
does anybody know which conditions usually trigger this fuel like smell and perhaps which engine models are more prone to such condition?
the fact that it goes away when flying let me me think something related to systems used when on ground
The air quality at an airport is horrific, in general, and as long as the plane is on the ground, it will be moving that air into the cabin.
People notice it because you go from highly filtered, airport air, to unfiltered air on the jetway, to possibly filtered (depending on specifics) air from the ground equipment, to bleed pack air.
It goes away when you are flying because the air quality 4000 feet above the airport is so much better.
The oil seals in a jet engine are not magically perfect, and so there is absolutely some miniscule amount getting into bleed air. But bleed air comes out from the compressor section, before any fuel can be there, and modern jet engines are exceptionally good one way valves (compressor stall is the term for when they aren't). Engine oil consumption is also monitored for every single flight, but not to that level of precision.
If the smell goes away in the air, it cannot be related to small amounts of oil vapor coming from the engine compressor section. Because that would still be present at 30k feet.
If you think of the last 10 flights you were on, how many had the gym sock smell? That's the real occurence rate. I'd say in my experience across all airlines its around 7/10 flights I can detect via smell a fume event.
If anything smelled it's usually due to a passenger. But nothing from the aircraft itself
Politely, I don't believe you haven't noticed the smell - this statistically is impossible when at an airport with multiple planes. You can smell it daily, at any airport terminal of your choosing, impossible to ignore when closer to the gates. It's a smell powerful enough to not get eaten by the various encapulation, ozone generators, and air fresheners used in public commerical environments like airports. The smell comes through from the planes and gangways into the terminal itself.
Next trip: With a clear nose, smell the air at the airport entrance and then compare this with the smell closer to your gate. The contaminated airs smell it's very similar to a wet locker room or gym bag that was left for days without cleaning. You won't ever miss it again, and your stat will flip to detected in 50 out 50 visits.
Since airlines consolidate on specific types, it is possible that some travelers experience this problem often and others very rarely.
Through no choice of my own, I seem to only fly on Boeing 737s, but the one recent time I was on an Airbus (A321neo) there was a distinct exhaust odor upon engine startup.
Coincidentally, when I am flying anywhere in Asia, I get none of this. I'd unironically rather be on an Indian airline for most flights because for all the flack that Indian people get about cleanliness, they're far more likely than the average gringo to have used a bidet at some point in their lives.
Even in a perfectly working bleed air system, the air comes from outside the plane, which on the tarmac of an airport, is god awful, shitty, and not at all healthy.
Lot's of other commenters talking about how the smell goes away at altitude.
Because it doesn't come from the packs (except in fume events), and what people are usually smelling is that airports have very bad air, and that air is much cleaner at 30k feet.
The miniscule oil vapor/droplets that are making their way into the bleed air system from engine compressor seals will still happen at 30k feet. If you don't smell something at all times on a plane, it cannot be coming from that.
This level of contamination would be like working at a gas station, which can be a health hazard. OSHA regulates air quality for employees working around hydrocarbons.