by the seat of one's pants

(fly) by the seat of your pants (do something by intuition or instinct rather than experience or prior knowledge) — делать что-л. по наитию, по непосредственным ощущениям, инстинктивно; нутром; импровизировать, действовать по обстановке; ~ по инерции, ~ на автопилоте (контекст.)

Example 1: When we started our business we were flying by the seat of our pants.

Example 2: If you asked me twelve years ago for advice on starting a business, I would have said "take the plunge first and work out the details later." Ask me that same question today and wouldn't even think of taking that fly-by-the-seat-of-your-pants approach.

Example 3: Some people do better flying by the seat of their pants than others who have had a lifetime of experience. (Boye De Mente)

Example 4: You live by the seat of your pants, and you hope that you are healthy and you don't get into an accident.

Example 5: Most plein air painters agree that looking for a formula doesn't give the best results. "When you are painting plein air you are essentially flying by the seat of your pants — it's a gut reaction," says Jean LeGassick, the vice president of the Plein-Air Painters of America (PAPA). "I rarely have time to analyze my composition until after the fact." (American Artist)

Example 6: My first attempts at studying intuition were undertaken in the field. I had the hunch that intuition was the key to individual and collective success in all human endeavors. This became my main hypothesis. Seeking to explore this hypothesis, I approached companies to see if their key decision-makers were intuitive. At the time, my research tool was an Intuition Profile Survey.

I discovered, to no surprise, that intuition was generally held to be disreputable. Worse, I found that the more an organization flew by the seat of its pants, and the more the organization became human-service related, the more unwilling the organization was to permit us to study intuition in its ranks. By now, I had followed Linnaeus's example and taken steps toward a classification structure for the whole phenomenon of intuition. (Daniel Cappon, IQ2)

Relates vocabulary
[gut feeling]
This expression goes back to the early days of airplanes when pilots guided their planes by "feel" rather than instruments.