UPS: Atmospheric Conditions Affecting Global Aviation

[Alley_Dweller]

On their web site, UPS has the following service alert (it may change or be removed when you read this):

Atmospheric Conditions Affecting Global Aviation May Cause Delays

Due to atmospheric conditions that have affected aviation globally, some shipments may experience unavoidable delays.

Contingency plans are in place and UPS is working to move shipments to their final destinations as quickly as conditions permit.

This sounds really scary. I have googled for “Atmospheric Conditions Affecting Global Aviation” and variations thereof and can find nothing about unusual aviation problems today. Does anyone know what they are talking about?

[friedo]

Volcano eruption in Indonesia is my guess.

ETA: Link.

[Richard_Pearse]

@friedo

Volcano eruption in Indonesia is my guess.

ETA: Link.

Maybe. Indonesia volcanoes erupt relatively frequently though. It could be a GPS issue that has been affecting a number of aircraft.

hackaday.com/2019/06/09/gps-and-ads-b-problems-cause-cancelled-flights

[friedo]

Unless it’s a severe malfunction ( ), a GPS issue would not be an atmospheric condition, surely. And I don’t think UPS flies any CRJ’s.

On second thought, maybe there’s some solar flares or something causing ionization that is interfering with GPS. That would be an atmospheric issue.

[Richard_Pearse]

@friedo

Unless it’s a severe malfunction ( ), a GPS issue would not be an atmospheric condition, surely. And I don’t think UPS flies any CRJ’s.

On second thought, maybe there’s some solar flares or something causing ionization that is interfering with GPS. That would be an atmospheric issue.

“Atmospheric conditions” could just be a lost in translation type thing between the tech people and the PR people. Or it could be that it wasn’t fully understood when the blurb was written. It is affecting more than just CRJs. Information in this PPRuNe threadsuggests it is all aircraft fitted with Rockwell Collins GPS / ADSB units.

Anyway, I don’t see any volcanic ash areas shown on the SIGWX charts for the US (or elsewhere). If the link works, you can browse the other areas. https://aviationweather.gov/progchart/high?region=a

Click the “info” button for a legend.

[gnoitall]

@friedo

Unless it’s a severe malfunction ( ), a GPS issue would not be an atmospheric condition, surely. And I don’t think UPS flies any CRJ’s.

On second thought, maybe there’s some solar flares or something causing ionization that is interfering with GPS. That would be an atmospheric issue.

Yes. The ionosphere is part of the atmosphere, and ionospheric scintillation affects GPS accuracy.

@NOAA Space Weather Prediction Center

Ionospheric scintillation is the rapid modification of radio waves caused by small scale structures in the ionosphere. Severe scintillation conditions can prevent a GPS receiver from locking on to the signal and can make it impossible to calculate a position. Less severe scintillation conditions can reduce the accuracy and the confidence of positioning results.

[sitchensis]

I bet the GPS is having a hard time utilizing the SBAS signal to compensate for the ionospheric conditions.

[Alley_Dweller]

Thanks for all your replies.

The alert has been taken down, so it seems like the atmospheric conditions have resolved themselves. I never realized GPS-based systems could be so fragile.