Strict Aviation Safety Regulations: Why Can’t Mobile Phones Be Air Transported Casually? Decoding the Five Core Restriction Reasons

When checking in at the airport, you are likely to be told by staff: “Mobile phones must be carried with you and are prohibited from being placed in checked luggage”; if you plan to send a mobile phone via air courier, the courier company will require multiple certificates and restrict the number of items sent. This is not simply “cumbersome procedures” but strict control over mobile phone lithium batteries in air transport. As the fastest logistics method globally, air transport’s characteristics such as high-altitude environment, confined space, and high pressure difference form a natural conflict with the chemical risks of lithium batteries. Data from the International Air Transport Association (IATA) shows that there were 23 lithium battery safety incidents in air transport worldwide between 2023 and 2024, with mobile phone lithium batteries accounting for 52%, making them one of the main hidden dangers to aviation safety. Why can’t mobile phones be air transported casually? This article will deeply decode the five core restriction reasons from dimensions such as risk nature, environmental adaptability, and regulatory requirements, uncovering the safety logic behind strict aviation transport regulations.

I. Core Reason 1: The “Air Amplification Effect” of Lithium Battery Thermal Runaway

The risk of lithium battery thermal runaway is sharply amplified in the aviation environment, becoming a “fatal hazard” threatening flight safety. The essence of this risk lies in the serious incompatibility between the chemical properties of lithium batteries and the air transport environment, and the high-altitude scenario makes originally controllable risks unpredictable.

(I) The “Air Chain Reaction” of Thermal Runaway

The electrolyte of mobile phone lithium batteries is an organic flammable liquid, with a safe temperature threshold of 80℃ under normal conditions. However, in air transport, multiple factors can jointly trigger thermal runaway. When the aircraft encounters turbulence, mobile phones in the checked luggage compartment may suffer severe collisions, causing deformation of the battery casing and short circuits between the positive and negative electrodes. The heat generated instantly causes the electrolyte temperature to exceed the critical value. At this time, flammable gases such as methane and ethylene produced by electrolyte decomposition cannot diffuse in the confined cargo compartment, and pressure accumulates rapidly. More dangerously, the air pressure at high altitudes is only 1/3 to 1/2 of that on the ground. Low air pressure lowers the ignition point of flammable gases and accelerates gas expansion, causing the battery to explode within a few seconds. The flame temperature generated by the explosion can reach over 600℃, which not only burns surrounding goods but also releases highly toxic gases containing fluorine and phosphorus, seriously endangering the lives of crew members and passengers.

(II) “Risk Superposition Factors” in Aviation Scenarios

The special environment of air transport amplifies the safety risks of lithium batteries from multiple dimensions. Firstly, aircraft cargo compartments are divided into pressurized and unpressurized cabins. Most lower cargo compartments of passenger planes are semi-pressurized, with an altitude of over 3,000 meters. The low-pressure environment directly weakens the structural stability of lithium batteries, making the battery casing more prone to deformation due to collisions. Secondly, the severe acceleration and impact force generated during aircraft takeoff and landing are equivalent to 10 times the intensity of the “1.2-meter drop test” for mobile phones, far exceeding the impact resistance limit of lithium batteries. Finally, the temperature fluctuation in the cargo compartment is extremely large, reaching up to 55℃ in summer after exposure to the sun and as low as -20℃ in winter. Extreme temperatures damage the chemical stability of the battery, reducing the safety threshold of the electrolyte by more than 30%. The superposition of these factors makes the probability of thermal runaway of mobile phone lithium batteries in air transport 8 times that of land transport.

(III) Real Case: An Irreversible Air Crisis

In July 2024, a Boeing 777 passenger plane flying from Frankfurt to New York encountered a cargo compartment smoke alarm over the Atlantic Ocean. The crew urgently activated the fire-fighting system and made an emergency landing in Iceland. Investigations revealed that the source of the smoke was a second-hand mobile phone in a checked luggage, whose battery triggered thermal runaway due to turbulence and collision. Due to the confined cargo compartment, toxic gases diffused rapidly, causing 3 crew members to experience difficulty breathing, severe damage to the aircraft’s internal equipment, and a direct economic loss exceeding 12 million US dollars. Similar cases are not uncommon. IATA statistics show that there were 11 serious aviation safety incidents caused by air transport of mobile phone lithium batteries worldwide between 2020 and 2024, including 2 leading to emergency landings and 3 resulting in cargo compartment burnout. These cases fully illustrate that the thermal runaway risk of mobile phone lithium batteries is highly destructive in the aviation environment and is an “unbearable weight” for aviation safety.

II. Core Reason 2: The “Inherent Limitations” of Emergency Response in Air Transport

Unlike land transport, once a lithium battery safety incident occurs in air transport, emergency response is extremely difficult, and there are almost no effective fire-fighting conditions. This is also a key factor restricting the casual air transport of mobile phones.

(I) The “Ineffectiveness” of Cargo Compartment Fire-Fighting Systems

The fire-fighting systems equipped in aircraft cargo compartments are mainly designed for ordinary solid fires, using carbon dioxide or halon-based fire extinguishers, but these fire extinguishers are completely ineffective against lithium battery fires. The essence of a lithium battery fire is a chemical reaction between metallic lithium, oxygen, and moisture, belonging to a “self-sustaining fire” that can continue to burn even in an oxygen-free environ