One of the many baffling aspects of the MH370 disappearance is the absence of radar data after the plane left Malaysian primary coverage at 18:22 UTC. If, as is generally presumed, the plane took a sharp left turn shortly afterward and flew into the southern ocean, it should have remained visible to Indonesian radar for more than an hour. Yet Indonesian military officials insist that nothing appeared on their radar screens.
This is an issue that has gotten less attention than it deserves, and for understandable reasons. Indonesia is a developing country, and a sprawling one at that. With a land area the size of Western Europe, it spans the same east-to-west distance as the continental United States. So one might reasonably assume that the country lacks the ability to comprehensively monitor its airspace. Why shouldn’t MH370 have passed through without a trace?
In fact, though, Indonesia has quite a capable air defense radar system, and one which it utilizes quite aggressively. In the last month alone, its air force has intercepted three civilian planes which wandered into the national airspace without first getting the proper permission.
The westernmost part of the country is covered by the Indonesian Air Force’s Radar Unit 231 at Lhokseumawe in Aceh, Northern Sumatera. The unit is equipped with a Thomson-CSF TRS-2215 radar, the type pictured above. The system, Indonesian military officials say, is capable of detecting aircraft up to 240 nautical miles away.
It demonstrated its capability last year, when the unit detected a Dornier 328 twin turboprop entering Indonesian airspace from the west. The plane was ordered to land at Sultan Iskandar Muda airport in Banda Aceh. It turned out to be a US Air Force Special Operations plane carrying five crewmembers; the pilot claimed he had been running low on fuel and didn’t realize that his paperwork to enter the country had expired. After being impounded for a few days the plane and its crew were allowed to leave.
Based on its specs alone, Radar Unit 231 (so much easier to spell than Lhokseumawe!) should easily have been able to detect MH370. The radar track released by the Australian Transport Safety Board (ATSB) in June shows that the plane came within 60 nautical miles of the installation before it disappeared from Malaysian and/or Thai military radar. Afterwards, according to the consensus view, the plane’s track should have stayed within the radar’s viewing range as it headed west, made a turn to the south, and proceeded into the southern Indian Ocean. (See map after the jump)
So how could the Indonesians have seen nothing?









