# How We Measure MH370 Drift Time

My previous article yesterday examined the “average drift time” postulated by Godfrey, Iannello, et al in an informal paper titled: “The Probable End Point of MH370”. The paper is dated February 12, 2017 and was distributed via Dropbox.

The foundation assumption in the Godfrey paper is that the 508 days that elapsed between the presumed crash of MH370 on March 8, 2014 and the flaperon’s discovery on Reunion Island is an accurate and useful estimate of drift time across that expanse of ocean: some 4,581 km or 2,473 nm.

It cannot be stressed too much that the 508 days that elapsed between March 8, 2014 and July 29, 2015 is arbitrary and a wholly unsatisfactory estimate of drift time across the Indian Ocean. It is in fact whimsical.

NOAA satellite-tracked drifters have been in the Indian Ocean for about three decades. They update their positions via satellite four times each day. We know where they are and how long it takes them to go from their respective points of deployment to any location they happen to be during their drift lifespan.

While we have all of this glorious NOAA drift data, working with it is a lot of work. It is complicated and it takes time to understand its subtleties. (I certainly do not claim to know all there is to know about those drifters; I simply consider them a very rich source of information that must be used with caution.)

For example, there are at least 14 of those NOAA drifters that crossed the Final Arc where MH370 is believed to have come down. (See the Excel excerpt below)

If one simply calculates the time it took each of those drifters to reach a NOAA-defined endpoint … counting drift time back from the date of original deployment … we get a ridiculous estimate for average drift time. The reason it is ridiculous is because only actual drift time from Point A (Final Arc) to Point B (Mascarenes) is relevant to aircraft-related debris drift time estimates. (For my purposes, drifters that fail to beach on a Mascarene Island – nearly all of them – are considered to be terminated when they reach 50°E longitude (Madagascar’s northeastern shore).

Excel Excerpt: NOAA Satellite tracked drifter statistics for drifters crossing the Final Arc where MH370 is believed to have crashed.

Not only do we have to manually go through drifter records to figure out when and where each of them crossed the Final Arc, we have to make sure they didn’t cross the final arc again before ultimately reaching our definition of a proper end point (landfall on a Mascarene Island, or 50°E).

In fact, of the 14 NOAA buoys shown above that initially merited review, five crossed the Final Arc more than once. If we fail to remove superfluous drift time, we end up with enormously incorrect average estimates of drift time, and that is precisely what happened to Godfrey, et al.

Similarly, some of those drifters continue to move west and south AFTER they arrived at Madagascar’s shores. All of that additional drift time has to be removed to end up with useful average drift time estimates.

In yesterday’s article I noted that average drift time for all 14 drifters was 227 days. If I remove the drifter that ended up north of the Mascarenes (#18689), and the two drifters that did not reach the Mascarenes (#9727915, #11270030), the average only goes up 4 days to 231 drift days. That works out to about 7.7 months. In other words, debris from MH370 should have been washing up on the Mascarene Islands in September and October 2014: roughly the same time Australia and Fugro Equator began using bathymetric scanners to examine seafloor contours 2,000 km southwest of Perth.

By publishing some of my work here, I urge others to check it and, if any of it appears to be incorrect, bring it to my attention. Only in this way will we ever agree on a likely terminal location, which I currently believe is very near Batavia Seamount.

The following charts show drift paths, average latitude “crawl”, and other bits of information relevant to determining how MH370 debris arrived in the Mascarene Islands, and beyond.

NOAA Satellite tracked drifters that crossed the Final Arc and reached the Mascarene Island area. This shows, among other things, how tight the drift path is between about 100°E and 50°E.

Shown in magenta are NOAA satellite tracked drifters that either drift much farther north than most other drifters, or that did not complete the journey to the Mascarene area.