Question: How would you weigh a aeroplane without scales?

Alternative Question Phrasing:

How would you determine the mass of a plane without scales?
How would you weigh a jet plane without weighing scales?

Follow-up questions:

How did you come to that conclusion?
How would that method work?
This plan has a special configuration that should not be tampered with, so taking the plane apart piece by piece is not possible.

Question Details:

Question Type:

Unconventional

Skills:

Basic – Critical Thinking,Basic – Mathematics,Basic – Science and Logic

Abilities:

Cognitive – Category Flexibility (Mental Flexibility),Cognitive – Deductive Reasoning,Cognitive – Mathematical Reasoning,Cognitive – Originality,Cognitive – Problem Sensitivity (Problem Recognition),Cognitive – Speed of Closure (Thinking Speed),Cognitive – Visualisation

Work Activity (Task):

Information Input – Estimating Characteristics of Objects, Events, or Information,Mental Processes – Making Decisions and Solving Problems,Mental Processes – Processing Information,Mental Processes – Thinking Creatively (Creativity)

Work Style (Person-Job Fit):

Analytical Thinking,Innovation

Question Frequency

Question Difficulty

What to look for in an answer:

You are looking for the correct answer of: flying the plane onto an aircraft carrier or large ship, and then measuring the ship’s water displacement. You are also looking for the creativity and thinking behind working our an answer.

Red Flags to Watch For:

If the interviewee does not attempt the question. If the interviewee continually insists on giving answers that go against the conditions of the question, that is, using a weighing scale of some form. Not having the ‘correct’ answer is not necessarily a red flag.

Sample Answer:

Get an aircraft carrier and mark where its waterline is. Fly the plane onto the aircraft carrier and mark where the new waterline is. Fly the plane off the aircrft carrier. The aircraft carrier should now be floating back at where the original waterline was. Either load items of known weight onto the aircraft carrier until it reaches the waterline when the plane was on it, or measure the amount of water displaced between the waterlines.

Other answers exist, such as flying the plane high up into the sky, letting it drop to the ground unpowered, and measuring how long it takes to reach terminal velocity.

Question Source: Unknown