Another Police Helicopter

[dbacksfan 2.0]

https://defensescoop.com/2025/01/30/army-helicopter-black-hawk-fatal-crash-potomac-not-using-ai-sources-say/

Would be implemented with defense contractor lockheed martin. 

So according to the article, 3 years ago Lockheed Martin did a couple of experimental flights with MX versions of a UH-60. Seems that people made a huge stretch from a couple of very controlled experimental flights to they've been conducting flights up and down the Potomac in extremely congested airspace.

[Red Arrow]

§ 91.217 Data correspondence between automatically reported pressure altitude data and the pilot's altitude reference.

(a) No person may operate any automatic pressure altitude reporting equipment associated with a radar beacon transponder—

(1) When deactivation of that equipment is directed by ATC;

(2) Unless, as installed, that equipment was tested and calibrated to transmit altitude data corresponding within 125 feet (on a 95 percent probability basis) of the indicated or calibrated datum of the altimeter normally used to maintain flight altitude, with that altimeter referenced to 29.92 inches of mercury for altitudes from sea level to the maximum operating altitude of the aircraft; or

(3) Unless the altimeters and digitizers in that equipment meet the standards of TSO-C10b and TSO-C88, respectively.

(b) No person may operate any automatic pressure altitude reporting equipment associated with a radar beacon transponder or with ADS-B Out equipment unless the pressure altitude reported for ADS-B Out and Mode C/S is derived from the same source for aircraft equipped with both a transponder and ADS-B Out.

[Doc. No. 18334, 54 FR 34304, Aug. 18, 1989, as amended by Amdt. 91-314, 75 FR 30193, May 28, 2010]

[dbacksfan 2.0]

Red, so if I'm reading correctly from your comment and and some searching on that regulation, it means that to report ADS-B it must use the aircrafts actual altimeter  and be certified accurate to within 125' based on using 29.92 ins. mercury, or sea level and certified for that particular altitude system in the aircraft. Am I at least in the park and it's not Yellowstone?

[Red Arrow]

Red, so if I'm reading correctly from your comment and and some searching on that regulation, it means that to report ADS-B it must use the aircrafts actual altimeter  and be certified accurate to within 125' based on using 29.92 ins. mercury, or sea level and certified for that particular altitude system in the aircraft. Am I at least in the park and it's not Yellowstone?

Not quite.  The altitude source can be an encoding altimeter (with electronics to communicate with the transponder) or it can be another device called a blind encoder (also with electronics to communicate with the transponder). A blind encoder is connected to the aircraft static pressure system, same as the altimeter, but the pilot cannot see or adjust it.  In either case, it must be tested every other (2) year for accuracy.  Large aircraft may have some other device as part of a Flight Management System but those are beyond my knowledge base.