The Real Reason Airplane Tires Are Filled With Nitrogen

Big airliners fill their tires with nitrogen, not ordinary air. The reason most people give sounds right, but it is not why the rule exists. Here is the real reason, and the proof behind it. CHAPTERS 0:00 Cold open 0:21 The question and the popular answer 1:22 What an airliner tire goes through 2:02 The real answer 3:11 Mexicana flight 940 4:06 THE PROOF, part 1: the investigation 5:02 THE PROOF, part 2: the lab test 6:09 From a lab result to a rule 6:57 And your car? 7:24 Ending The diagrams are simplified illustrations. How sure are we about each claim? See the pinned comment (after you watch). SOURCES FAA proposed rule, 51 FR 30670 (1986): https://www.govinfo.gov/content/pkg/F... FAA Airworthiness Directive 87-08-09, 52 FR 13633 (1987): https://www.govinfo.gov/content/pkg/F... FAA final rule, 58 FR 11778 (1993): https://www.govinfo.gov/content/pkg/F... 14 CFR 25.733 (tires): https://www.ecfr.gov/current/title-14... 14 CFR 25.735 (brakes): https://www.ecfr.gov/current/title-14... 14 CFR 25.729 (landing gear): https://www.ecfr.gov/current/title-14... Mexicana flight 940 accident report (SCT/DGAC, Mexico, 1986, Spanish): https://asn.flightsafety.org/reports/... NHTSA nitrogen tire study, DOT HS 811 094 (2009), archived official copy: https://web.archive.org/web/202104120... NIST Chemistry WebBook (gas data): https://webbook.nist.gov/chemistry/fl... FAA Aviation Maintenance Technician Handbook, Airframe Vol. 2, ch. 13: https://www.faa.gov/sites/faa.gov/fil... Goodyear Aviation tire care manual (2024): https://goodyearaviation.com/resource... Michelin aircraft tire manual (2021, PDF download): https://www.faasafety.gov/files/gslac... Boeing 737 airport planning document (2025), section 7.2.1: https://www.boeing.com/content/dam/bo... NASA Earth fact sheet: https://nssdc.gsfc.nasa.gov/planetary... NASA Glenn atmosphere model: https://www.grc.nasa.gov/www/k-12/air... Example of the popular answer: SlashGear (2025): https://www.slashgear.com/1820852/air... In memory of the 167 people lost on Mexicana flight 940, 31 March 1986.