Estimation question

Estimate the weight of of a 747 airplane.

Practice this question out loud. An AI interviewer asks it, follows up like a real interviewer would, and scores your answer. Type or speak.

What this question tests

Estimation: can you build a bottom-up structural estimate for a physical object using component weights and material reasoning.

Break the 747 into major components: fuselage/airframe structure, wings, engines (typically four), landing gear, and interior fittings.
Estimate the airframe structure weight using aluminum/composite material density and approximate dimensions of a 747 (length roughly 70m, wingspan roughly 65m, state as assumptions).
Estimate engine weight: four large jet engines, each roughly several tons (state assumption per engine).
Estimate landing gear and interior fittings as a smaller additional weight component.
Sum the components to get an estimated empty aircraft weight, then note this excludes fuel and payload, which would roughly double the figure at max takeoff weight.
Sanity check the final number against known orders of magnitude for large commercial aircraft.

Breaks the aircraft into structural components (airframe, engines, gear) rather than guessing one number for the whole plane.
Distinguishes empty weight from max takeoff weight (including fuel and payload), a meaningful and often-missed distinction.
Uses plausible per-component weight assumptions (e.g. engine weight) rather than assumptions with no grounding.
States the final answer as a range and clarifies which weight definition it refers to.

Giving one number without clarifying whether it's empty weight or max takeoff weight, which differ hugely.
Not breaking the estimate into components, making the number impossible to sanity check.

How would your estimate change if asked for max takeoff weight instead of empty weight?
Which component's weight are you least confident about, and why?