The language of aviation is full of numbers, and dozens of them are buzzing around the investigation into the disappearance of Malaysia Airlines Flight 370.
The most crucial number — for those 239 missing souls aboard the flight and their friends and loved ones — is this one: 10. That's how many days Flight 370 has now been missing.
Here are some of the other major figures in the investigation:
Number of search paths being scoured for Flight 370.
Number of advanced U.S. aircraft — P-3 and P-8 anti-submarine warfare planes — staying to search after U.S. officials told NBC News the USS Kidd was preparing to return to normal Navy operations.
Number of words spoken in the last voice transmission from Flight 370. Malaysia Airlines quoted co-pilot Fariq Abdul Hamid as having said: "All right, good night."
Number of hours (specifically, five hours and 56 minutes) between Flight 370's last pickup on radar and its last known communication of any kind, a "handshake" with a British Inmarsat satellite.
Number of theories under investigation — but so far unsubstantiated:
- The plane landed somewhere, for reasons unknown, and isn't able to communicate with the outside world. Experts say that's technically possible but almost unimaginable.
- A "sudden catastrophic event," like mechanical failure or decompression, as when a plane carrying golfer Payne Stewart crashed in 1999.
- Hijacking or terrorism: No credible group is known to have claimed responsibility for the plane's disappearance.
- Crew sabotage — including pilot suicide, for example.
- Pilot error. This is considered unlikely, as both pilots were very experienced.
- "Outside human intervention," such as bad weather or a meteor strike.
Maximum number of hours Flight 370 could have flown with its total fuel load, according to the airline.
Number of countries whose territories are in Flight 370's possible flight paths.
Number of countries searching land and sea for Flight 370 as of Monday evening.
Number of ships searching for Flight 370 as of Monday evening.
Number of aircraft searching for Flight 370 as of Monday evening.
Number of passengers and crew aboard Malaysia Airlines Flight 370.
Number of runways where Flight 370 could have landed in an emergency, calculated by cataloging all runways 5,000 feet long or longer within the territories where it could have flown. (Credit: WNYC radio)
Minimum number, in feet, of runway required to safely land a full Boeing 777-200, according to Boeing. Landings can be attempted in as little as 5,000 feet in an emergency.
Maximum range, in nautical miles, of the Boeing 777-200ER.
Number of hours of flight experience logged by Flight 370's pilot, Zaharie Ahmad Shah.
Number of miles the last entity to have had contact with Flight 370 — that British satellite — is orbiting above Earth.
Number of square land and sea miles estimated to be in the overall search area.
"This is not just a needle in a haystack," said Royal Malaysian Air Force Capt. Izam Fareq Hassan. "It's a haystack that gets bigger and shifts under us due to the (ocean's) drift."
Jim Miklaszewski, Courtney Kube, Alistar Jamieson and Polly DeFrank of NBC News contributed to this report.