Lost In Metric Non-Conversion


By The Metric Maven

Isaac Asimov once wrote an interesting essay called Lost in Non-Translation. I don’t recall its details, other than he pointed out the considerable confusion caused by the difficulties that occur with translations from one language to another.

Our translation tale begins when I serendipitously ran across a small article in an old issue of the USMA’s Metric Today (July-August 2001 Vol. 36 No. 4 page 8) . I was surprised I’d never heard about this incident:


Eight people were killed and over 40 injured?—and this incident seems lost to metric history? The KE6316 event happened only about four months before the famous loss of the Mars Climate Orbiter that September—and the first metric incident, KE6316, that cost human lives, went comparatively unnoticed? This gobsmacked me. I immediately turned to Wikipedia and the flight mishap was listed. Here is what it has to say:

  • 15 April 1999Korean Air Cargo Flight 6316 (McDonnell Douglas MD-11) from Shanghai to Seoul took off despite the Korean co-pilot’s repeated misunderstanding and miscommunication with the tower and the pilot. The aircraft climbed to 4,500 feet and the captain, after receiving two wrong affirmative answers from the first officer that the required altitude should be 1,500 feet, thought that the aircraft was 3,000 feet too high. The captain then pushed the control column abruptly forward causing the aircraft to start a rapid descent. Neither was able to recover from the dive. The airplane plummeted into an industrial development zone 10 kilometers (6.2 mi) southwest of Shanghai Hongqiao International Airport. The plane plunged to the ground, hitting housing for migrant workers and exploded. Damage: Destroyed Injuries: 37 on ground Deaths: 8 (all 3 crew and 5 on ground) Airframe: Written Off[22]

When I read this account, I was floored to see that the metric-medieval unit confusion, which was at the root of the incident, was not included in the Wikipedia description of the accident. What on Earth? The article has a reference. Perhaps the reference is at fault? Let’s see what it has to say:

MD-11F cargo plane HL7373 was operating flight KE6316 from Shanghai’s Honqiao Airport to Seoul. The plane was  loaded with 68 tons of cargo and pushed back from it’s stand. Shanghai Tower then cleared the flight as follows: “Korean Air six three one six clear to destination flight planned route flight level two niner zero. After departure turn left direct to November Hotel Whiskey. Initially climb and maintain niner hundred meters. Departure frequency one one niner zero five. Squawk six three one six.” The engines were started and the airplane taxied to runway 18. Shortly after 4pm the flight was cleared for takeoff. After takeoff the first officer contacted Shanghai Departure and received clearance to climb to 1500 metres (4900 feet): “Korean Air six three one six now turn left direct to November Hotel Whiskey climb and maintain one thousand five hundred meters.”

When the aircraft climbed to 4500 feet in the corridor, the captain, after receiving two wrong affirmative answers from the first officer that the required altitude should be 1500 feet, thought that the aircraft was 3000 feet too high. The captain then pushed the control column abruptly and roughly forward causing the MD-11 to enter a rapid descent. Both crew members tried to recover from the dive, but were unable. The airplane crashed into an industrial development zone 10 kilometers (6 miles) southwest of Hongqiao airport. The plane plunged to the ground, plowing into housing for migrant workers and exploded.

There it is in the reference, Shanghai told them to ascend to 1500 meters and then maintain that altitude. The actual quotation is given. The first officer twice thought that the authorized altitude was 1500 feet despite the fact that initial altitude value of 900, and the second, 1500, were both given in meters. The captain immediately decreased the altitude, and went into a dive from which they could not recover and crashed into a construction area.

I doubt the author of the Wikipedia summary had any malice, or intentionally obscured the the fact that the root cause of this crash was a confusion between metric and antique measures. At least I hope this is the case. The first paragraph of the reference material quoted above is in meters and the second changed to feet without directly pointing out the metric-Ye Olde English confusion. It can easily be inferred with a careful reading. The Wikipedia article condensed the first paragraph of the reference prose into a single sentence and buried the source of altitude confusion, but left most of the second paragraph intact.

What I do think is that measurement itself is so out of the minds of most people in the US, that they will convert to Ye Olde English exclusively, and thoughtlessly bury the lede six feet under. All one reads in the Wikipedia account is there was confusion about the altitude in the cockpit, but not its root cause, which was a confusion between Ye Olde English units and metric. In the case of the DART incident, the metric-medieval conversion error was obscured by NASA by burying it within a tome of a report. Here are two catastrophic failures, DART and Korean Airlines KE6316, which are independent of the Mars Climate Orbiter debacle, that have been lost to metric history. Both incidents demonstrate that measurements matter.

If you liked this essay and wish to support the work of The Metric Maven, please visit his Patreon Page and contribute. Also purchase his books about the metric system:

The first book is titled: Our Crumbling Invisible Infrastructure. It is a succinct set of essays  that explain why the absence of the metric system in the US is detrimental to our personal heath and our economy. These essays are separately available for free on my website,  but the book has them all in one place in print. The book may be purchased from Amazon here.

The second book is titled The Dimensions of the Cosmos. It takes the metric prefixes from yotta to Yocto and uses each metric prefix to describe a metric world. The book has a considerable number of color images to compliment the prose. It has been receiving good reviews. I think would be a great reference for US science teachers. It has a considerable number of scientific factoids and anecdotes that I believe would be of considerable educational use. It is available from Amazon here.

The third book is called Death By A Thousand Cuts, A Secret History of the Metric System in The United States. This monograph explains how we have been unable to legally deal with weights and measures in the United States from George Washington, to our current day. This book is also available on Amazon here.

6 thoughts on “Lost In Metric Non-Conversion

  1. Very good post, Maven. It jogged my memory about, and I googled, Air Canada Flight 143 that made a power off landing at a former Canadian Air Force Base on 1983/07/23. Fortunately there were only a few minor injuries and all of the sixty plus passengers and crew on board survived and there were no injuries on the ground. The aircraft reportedly had faulty fuel gauges, which definitely complicated things, but the main problem was in the incorrect calculation of measuring the amount of fuel already in the tanks and in how much more fuel should have been added. Incorrect conversion factors were used in switching from imperial to metric units and were further complicated by not taking into consideration the temperature which affects the volume. Fortunately the captain was an experienced glider pilot, and that equipped him well in this situation, and the first officer had previously been stationed at the former base and knew its location. The universal definition of a good landing is one that one walks away from. It is a shame that the crew of KE6316 and those on the ground were not as lucky.

  2. I’m not denying that unit confusion is a factor, but at least two contributing factors you don’t mention:
    *The Chinese are using both unit system. Yes, takeoff control is in meters, but he was ultimately cleared to FL290 to destination, that is 29000 feet with altimeter setting at “standard” not actual. So where is the pilot supposed to switch between meters and feet? I don’t know either, but it certainly adds to the confusion.

    *Even if the pilot had been instructed to fly at 1500 feet, he is expected to make any altitude transition without appreciable undershoot or overshoot. To crash (0 feet) when aiming at 1500 feet is not acceptable control of aircraft. Had he hit another plane at 1500 feet or during descent, the metric error would have been a major factor. The pilot simply was not in control of his aircraft. The fact he was aiming at the wrong altitude is not really a factor because he wasn’t aiming at the ground. Bluntly, he missed.

  3. Wikipedia articles are not absolute. You have the power to edit in what is missing. If you feel it is wrong and misleading, then correct it.

  4. We would not have heard about this metres/feet mix-up if it had not ended in a fatal crash. Is it likely that there are more of this type of error that are not reported?

  5. Automation could perhaps finally catalyze a completely metric aerospace industry and flight control system (maybe distributed, in a self-regulating, network-like way, instead of centralized in control towers); even better, also, if some form of electromagnetic propulsion system(s) could eventually supersede today’s runway- (and oil-)based takeoffs and landings: i.e., ecological VTOL flights, everywhere.

    But how, and when? That’s the problem (as with US metrication and other important things – which people don’t seem to want to see, today, also because there’s currently no launch window to the future, for various reasons)…

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