As a nod to Titanic week, I'll post a note about beacons and debris fields in a bit. But fragments can't be flagged, tagged, or mapped on a grid unless the site is found first. What if the airplane never turns up?
Lost airliners may seem a problem confined to the wayback era of Lost Horizon ...
... a novel in which a DC-3 crash-landed in the Himalayan fastness, leaving the survivors on their own. Fortunately for them, the friendly burg of Shangri-La was just around the corner.
Do airliners still stray off the map in the post-WW2 era? That is, go missing, and stay missing?
Yes, but not often! One was Northwest Airlines Flight 2501, a westbound Douglas DC-4 that broke up in a storm over Lake Michigan on the night of June 23, 1950. Rescuers pulled human remains and floating debris from the lake's surface, but the plane's metal wreckage never turned up, despite sonar-assisted efforts in the last ten years. Most likely cause: in-flight breakup due to severe storms in the area.
Another was an Air Charter DH-90 Dragonfly, registration ZK-AFB, which went missing on a February 12, 1962, sightseeing flight from Christchurch to Milford Sound, NZ. The airframe looked like this:
Despite what's said to be the biggest search and rescue effort in New Zealand's history, the plane was never found.
The most recent missing-airliner case that comes to mind was a Pakistan International Airlines Fokker-27 turboprop with the call letters AP-BBF. It carried 54 people. Here's what a Fokker-27 looks like:
The last information about the August, 25, 1989, flight from Gilgit to Islamabad was a routine report transmitted seven minutes after leaving the airport.
Despite an intensive search along the flight path, no trace of passengers or plane has been reported since then. A focus for the search was Nanga Parbat, this 26,660-foot peak:
Two climbers who were on the peak at the time said they may have seen the PIA plane go by.
Next, a post explaining why it took so long for searchers to locate the submerged digital flight data recorder and cockpit voice recorder from Air France 447.