Discrepancies in Aircraft Runway Visible Range (RVR)

If your aircraft's instrument landing system cannot go below half a mile, you will find trouble with Jeppesen charts, which measure runway visible range by one-eighth of a mile increments.

jmiller

Friday, December 04, 2015 at 12:00 AM ET

Verified

Key Takeaways:

Jeppesen approach charts contain an error that incorrectly converts 1800 RVR to 3/8 statute mile (SM) visibility on some ILS approaches.
This conversion contradicts government regulations (TERPS, AIM, 14 CFR Part 91.175) which mandate 1/2 SM as the lowest legal visibility for CAT I approaches, even for 1800 RVR, by prohibiting interpolation.
Pilots relying on the erroneous charts could inadvertently violate regulations, leading to enforcement action; therefore, 1/2 SM must always be considered the minimum visibility for CAT I approaches, regardless of chart information.

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It’s rumored that bean-counters at TWA in the nineties determined that switching from Jeppesen to government charts would save $20 million a year. The idea was quickly squashed by the safety department. Twenty million a year wasn’t worth an accident due to misread charts.

Of chart providers, Jeppesen is arguably the best and inarguably the most popular, surpassing the U.S. Government’s AeroNav and Lufthansa’s LIDO products. But, underlying it all are humans, and we humans are a fallible lot. We make mistakes. This is exactly what Jeppesen did when it published approach charts with minimums of 1800 RVR being equal to 3/8 mile.