Yesterday (17th) Tim Vasquez provided links to weather satellite imagery of the SE Indian Ocean area on the 8th March.
http://www.pprune.org/8382068-post4888.html
His images are from around 0000 - 0200 UTC and are around 2km resolution. However there are 250m pixel images available from around 0300 to 0500 UTC available on this site:
Rapid Response - LANCE - Near Real Time (Orbit Swath) Images
It's necessary to type the date in the small box at top left, click on the relevant thumbnail and select a resolution. There are two sets of images, firstly the Terra satellite with earliest coverage, unfortunately about 3-4 hours after the last 'ping'. So only a persistent contrail would be visible. To my untrained eye there's no visible contrails over the open sea areas. I expect the professionals have already enhanced these images as part of the search.