Suggest all Ops Managers, and all flight crew that have a desire to have GPWS send their seasons greetings to:
Brett Portwood, Continued Operational Safety Technical Advisor, COS Program Management Section, Operational Safety Branch, FAA, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 817-222-5390; email: operationalsafety at the good ol' FAA dot GOV.
At this time, the constraints are to remove SA CAT I/II/III, Autoland, EVS and the like at the NOTAMed airports, but your GPWS system is also compromised, so expect warnings to go off. Just what you want is a warning system that goes off randomly, it results in a resistance to response that may affect real warnings. The insanity of this nonsense is breathtaking, the only realistic defence is to have VMC operations only below safety height, which should pretty much stop all turbine traffic in the east of the USA that may be subject to this NOTAM in the season of cheer... or risk repetitive false warnings resulting in resistance to response in real cases, that's what humans do. We are good at learning workarounds, and those workarounds tend to become pavlovian heuristics that have unintended consequences. Of course, Collins, Honeywell and co, can always come up with new LRRAs that operate on a new band, that shouldn't take more than 5 years to push through, and about 25K per aircraft, 3 times that for Boings and Airbusses etc...
Wish that the FAA and FCC had kept with just making a stew to go with yoghurt and tabbouleh instead of becoming amorous with the goats.
FAA 2021-23-12 DOCKET
At least IATA and IFALPA understands the issue, even if it was subsequently disregarded in the FAA AD...
IATA PROBLEM STATEMENT 27 NOV 20 MONTREAL
List of potential equipment failures:
Interference to RA operations can affect:
1. Autoland functions: This is particularly critical in low visibility auto approach like Cat II or III conditions. Pilots cannot conduct CAT II and III approaches if RA is malfunctioning.
2. EICAS/ECAM: Nuisance warning after take-off or during approach which will distract crew from their tasks at hand. This will lead to deterioration of operational safety levels.
3. False or missing GPWS alert: Anywhere in proximity to ground, this could inhibit some functionalities of the TAWS (Terrain Alerting Warning System) reactive modes which would remove a safety net in case against CFIT (Controlled Flight Into Terrain). Additional distractions for crews from tasks at hand, – “too low gear” and “too low flaps”, “don’t sink”,” terrain and pull up warning” and other alerts. A big concern is GPWS not triggering an alert when it should have done so, because of interference which can result in CFIT event!
4. Unreliable instrument Indications: This could contribute to an increased number of hard landings because of errors in automatic altitude indications and voice announcements.
5. Abnormal behaviours in Automatic Flight Systems: a. Autoland system b. Flight Control Laws (e.g. failure to transition to Flare law resulting in a higher than expected pitch on the flare; Retard function, etc.) c. Auto-throttle automatic stall protection. d. Auto Speedbrake deployment
Remember, your busses, big 'n little, use RA for determining control laws.... watch this space...
In spite of the perceptiveness of IATA and IFALPA in NOV 2020, we get 5G on the same band as the RA's????
WTF!