4 ms·
Layman’s explanation: When modern planes land in bad weather, especially fog, the height off the ground is determined by bouncing radio waves off the ground. E
by JCM9 5y ago
Layman’s explanation:
When modern planes land in bad weather, especially fog, the height off the ground is determined by bouncing radio waves off the ground. Essentially radar pointing down off the bottom of the plane. This provides added safety over the normal altimeter measurement using air pressure. 5G frequencies are too close to the frequencies used for this radar and so the theory is that this will cause dangerous interference that could cause issues during a critical phase of landing. Without these systems aircraft would not be able to use certain instrument approaches and thus couldn’t land during certain weather conditions when they can today. If the FAA pulls the plug on these it would cause big headaches during times when today planes can land without issue.
tldr 5G might stop you from getting to your destination on time or at all on a future flight.
- sokoloff 5y agoThat explanation is correct but somewhat incomplete. Precision approaches with low minimums (the decision point where a missed approach must be initiated) also have an alternate source of vertical guidance (in the typical case of an ILS, it’s a radio beam bounced off the ground and up along the approach path and the pilot has a very tight indication of whether they’re below, on, or above that beam). The radio altimeter is a secondary or tertiary source of height above terrain information, not a primary. Without a functioning radio altimeter, some aircraft on approach to some runways would have to use higher minimums than would be available if they have a functioning unit. This will contribute to some missed approaches or diversions in low weather. (Where a missed approach almost never ends in a crash in airline operations but rather a second attempt or a diversion.)