[gkedzierski]

"your vestibular system is your primary instrument"

This was a big no-no during my training. You are very prone to spatial disorientation and vestibular system illusions like leans, somatogravic illusion, etc. I was always taught (in the books and during flights) to trust the aircraft instruments.

(I trained in the UK)

[MaxBarraclough]

They're talking about flying VFR. You can't get the leans or somatogravic illusion flying in daytime VMC.

An attitude indicator is not required for VFR-only aircraft.

[krisoft]

You are right, but I believe gkedzierski is right too. It is indeed common for trainers to start telling these things to student pilots early on during their training. I think the reasoning behind that is to instil the right instrument scan practices while people are fresh in the cockpit before they even consider IFR training.

> You can't get the leans or somatogravic illusion flying in daytime VMC.

You are 100% correct on that. Just to explain to others reading us: VMC means visual meteorogical conditions. Roughly and informally that is when you can see. While IMC would be instrument meteorological conditions, that is roughly and informally when you can't.

Just to illustrate how dangerous these "leans" can be there is this NTSB report about such a case: https://www.ntsb.gov/investigations/AccidentReports/Reports/...

People might also know this one as the tragic helicopter accident which killed Kobe Bryant.

The pilot had 8,577 hours of total flight time, and he was the chief pilot of the company. So you would count him as an experienced pilot. Yet as he flew into thick fog, according to the NTSB report, he got the "leans". That is he had the illusion that he was ascending while in reality his airplane was banked and turning. Sadly they flow into a hillside and all 9 people aboard died. A tragic case.

It is hard to know exactly when the pilot lost all visual cues but according to the report there was about a minute between the pilot reporting to ATC that they are climbing to get over the clouds and them impacting the terrain. Things unfortunately can go sideways very fast in IMC.

[gosub100]

> I was always taught (in the books and during flights) to trust the aircraft instruments.

I'm just saying this for other readers, you probably know already, but the word "taught" is doing a lot of work here. Training for IFR requires many hours of being put into many situations designed to fool your vestibular system to get you to forcefully override it and just use the instruments. Many people crash because they ignore the instruments (due to task saturation) or in a panic, think they are faulty and trust their body. IMC is no joke.