So far there have been no airliner disasters specifically attributed to passengersâ digital devices. But experts worry about the sheer mathematics. The Royal Aeronautical Society in Britain estimates that even a single-aisle jet with only 100 passengers might have more than 500 lithium-ion batteries aboard. Those numbers, and the attendant fire risks, could eventually catch up with the air-traveling public.
The question is: What to do about it â besides issuing advisories?
The F.A.A. administrator, Michael P. Huerta, said in an email statement that the agency recognized that the batteries posed risks and that it was tracking all incidents in aircraft cabins âto help us determine what we can do.â Mr. Huerta urged passengers to put their devices âin a carry-on bag or other safe locationâ when not using them.
But the F.A.A. is in a tough situation. Under the regulatory rules, it cannot ground the Galaxy Note 7 until the Consumer Product Safety Commission orders a recall. On Friday, the safety commission said it was working with Samsung on the terms of a recall and urged owners of the phones to stop using them. On Saturday, Samsung offered new guidance to owners: Turn off your phone and bring it in for a replacement.
Congress has limited the F.A.A.âs ability to place restrictions on battery-powered devices on airplanes beyond the recommendations of the International Civil Aviation Organization, according to Laura Brown, an F.A.A. spokeswoman. The organization, a United Nations agency, says the devices should not be transported on passenger planes as cargo or in checked baggage. As for in-cabin use, the organization defers to each countryâs rules.
Any attempt to seriously restrict or even ban devices powered by lithium-ion batteries would probably face an outcry from travelers, who have come to consider them an indispensable part of modern life. There would also be the question of who would enforce such rules, and how. Airport security check-in processes are already long and tedious, without adding a new layer of scrutiny.
Until a few years ago, before the in-cabin use of phones and other electronic devices was allowed below 10,000 feet, it was widely known that passengers surreptitiously defied the rule. Flight attendants complained that it was impossible to police.
So the goal is to contain the hazard. In the event of a lithium-ion battery fire in flight, F.A.A. standards may help minimize the damage.
Seat covers, carpets, curtains and dividers are made of special materials that are flame retardant, even against a lithium-ion battery fire, which burns in the neighborhood of 1,000 degrees Fahrenheit, according to Isidor Buchmann, an engineer who runs the informational site BatteryUniversity.com.
Some experts say those standards could suffice.
âItâs damned near impossible to propagate a fire on an airplane,â said George J. Ringger, an aeronautical engineer with his own consulting company who specializes in cabin interiors. âCould a passenger get burned? Yes. Would there be smoke that would propagate in the cabin? Do crews have protocols? Yes.â
But some other fire and safety experts are not as sanguine. A laptop battery fire could take hours to burn itself out. And the smoke emitted would be abundant and toxic.
Michael Gilchrist is an engineer and co-owner of PlaneGard, a maker of a case meant to contain the fire and smoke if a battery starts to malfunction. Customers include Air Tahiti Nui, which carries the PlaneGard case on transoceanic flights.
âWith a full-blown laptop, you see what happens,â Mr. Gilchrist said. âYou have a 35- or 40-minute event. That could cause a lot of problems.â
There is no global database with comprehensive information about battery fires from electronic devices in the cabins of passenger airplanes. The F.A.A.âs tally â 19 fires in the last five years â is based on what the agencyâs spokeswoman, Ms. Brown, called an âinformal list.â
The Australian authorities investigating the Qantas event in May found that there had been 17 episodes in their jurisdiction during the same period.
A spokesman for the airline industry group, the International Air Transport Association, said its members had reported 24 cases in which a battery overheated and caught fire or released smoke in the passenger cabin.
But Mr. Gilchrist says events often go unreported. âThe reporting is horrendously bad, but if you sit and talk with a pilot or an aircrew, theyâll say it happens once a month,â he said. âThis is not a remote occurrence.â
In 2013, after considerable pressure from customers, airlines began allowing passengers to use electronic devices from gate to gate. As the number of devices passengers typically carry has increased, more accommodations have been made for their use, including USB ports that let people watch in-flight movies on their own devices and electrical outlets for chargers.
âThe advent of electronic devices, as well as an electric plane, raises new issues that ought to be addressed very carefully by the regulatory authorities,â said N. Albert Moussa, founder of the fire safety company BlazeTech and a consultant on airplane fire hazards.
Although the Samsung recall is renewing public awareness of the problem, Mr. Moussa is not optimistic that it will prompt long-term solutions. âHistorically, the community takes real action,â he said, only âwhen an accident happens.â