Before Takeoff Check

The preflight inspected the airframe cold; the runup verifies the systems under power right before I bet a takeoff on them:

• Ignition redundancy
• Carb heat
• Engine instruments in the green
• Flight instruments set
• Controls free and correct
• Configuration (flaps, trim) matching the takeoff I briefed

It's the last chance to catch a malfunction while stopping is free (AFH ch 2, POH).

The mag check tells me several things at once:

• The RPM drop on each mag confirms that mag is actually being tested and the timing is roughly right — no drop at all suggests a broken P-lead (a hot mag)
• An excessive drop or rough running points to a fouled plug or failing mag
• The difference between the two mags matters too: a big split means one system is unhealthy

A fouled plug can often be cleared by leaning aggressively at moderate RPM for a bit, then rechecking — if it won't clear, taxi back.

Pointed as close to into the wind as practical for engine cooling, and:

• On a surface that won't sandblast the prop or throw stones behind me
• Not aimed at other aircraft or people with my prop blast
• Where I can still watch for traffic

I also make sure the nosewheel is straight and the area ahead is clear in case the airplane creeps.

My briefing covers runway and expected performance (rotation speed, distance versus available), initial heading/altitude, and the emergency plan by phase:

• Before rotation: abort on the runway for anything abnormal
• Below my turnaround decision altitude: engine failure means land ahead, within roughly 30 degrees either side
• Above it: the options open up

Saying it out loud pre-loads the decision so an actual failure gets action, not deliberation. I also confirm the takeoff performance numbers I calculated still match reality — wind, runway, weight.

Anything abnormal before rotation is the trigger. The examples I brief:

• Engine roughness
• RPM not reaching the expected static value
• Airspeed not alive by my callout point
• A door popping open
• A warning light
• An animal or aircraft on the runway

The decision is pre-made — abnormal equals abort — because inventing a decision at 50 knots wastes the runway I need to stop.

Re-run the numbers before accepting:

• New runway length and surface
• New wind components — is it now a tailwind or a bigger crosswind?
• Obstacle picture
• Emergency plan — the land-ahead options are different off a different runway

If the new runway doesn't work for my performance or comfort, the answer to ATC is 'unable.' A runway change also resets my wake-turbulence and taxi-route thinking.

Wingtip vortices sink and drift with the wind, and are worst behind heavy, slow, clean airplanes. My avoidance depends on what the big airplane is doing:

Behind a large departing aircraft: rotate before its rotation point and climb upwind of its path.

Behind a landing large aircraft: lift off beyond its touchdown point.

If timing is tight, waiting two to three minutes costs nothing — I can tell tower I'll hold for wake turbulence (AIM 7-4).

The checklist gets done thoroughly but I keep a scan outside — traffic on final, aircraft taxiing behind me, and my hold-short position. If ATC interrupts mid-checklist, I answer, then back up several items rather than trusting that I remember where I was. Rushing the runup because someone's waiting behind me is exactly the external pressure the ACS wants me to recognize and reject.