View Full Version : Honeywell 660 Radar on 139 specific, and helicopters in general
Winnie
21st Jan 2024, 18:28
So a questions for the experts. We are having a friendly argument about WHY we have the radar on at the least standby when operating the helicopters.
From my own "common wisdom" which isn't very wise I'll admit, we have always left them on because of vibrations damaging the gimbal mounts, and obviously because if you need it, it won't take ages to warm up.
I've searched the books, Honeywell 660 manual, Primus Epic manual, Flight Safety and Leonardo training books, company SOP. Only guidance is company and Flight Safety says ON on checklists...
So to the panel of experts, anybody have a good reference for WHY?
Cheers
Winnie
megan
22nd Jan 2024, 01:05
On a gin clear day never saw reason to turn it on, interested to see what knowledgeable folk have to say, does the practice cause problems with the system? Didn't seem to in as much as we never had radar problems, iron gyros were another matter which were replaced with solid state.
Agile
22nd Jan 2024, 02:46
interested to see what knowledgeable folk have to say
Unknowledgeable folk here... just experienced with complex systems those many components have convoluted interactions.
Sometime its interesting what a sub-system those functionality is far removed can create such an unforeseable implication.
it would be likely that the aircraft is tested and qualified with all system on. testing with partial system off is probably an area that receive less attention.
Pittsextra
22nd Jan 2024, 07:18
Only guidance is company and Flight Safety says ON on checklists...
So to the panel of experts, anybody have a good reference for WHY?
Cheers
Winnie
no expert but my impression would be in SOP is to have an ON/OFF option you’d then have to give further consideration to what equals ON or OFF, serviceability and if OFF when it becomes ON. If there is no life limit issues then I suspect easier to leave on.
Scanner stability would be my suggestion - keep it powered up to stop it flopping around and getting damaged.
steve_oc
22nd Jan 2024, 09:47
Agree. If the system is powered, the antenna is kept in place and stable so no risk of damage to components, which there might be is the system was unpowered. Also, why go to the bother of having a radar and not using it?
JimEli
22nd Jan 2024, 14:26
You might be looking in the wrong location.
Does the fire department only test hydrants just before a fire?
My guess would be that the aircraft was tested and certified in that configuration. And it’s an installed system, so why wouldn’t be on?
FWIW, FAR part 135.175 (for large transports) requires it to be operational when detectable weather is reported. If it's not on, how does one know it's operational?
megan
22nd Jan 2024, 15:45
why go to the bother of having a radar and not using itUsing it for what on a gin clear day? Besides, we only flew VMC, cough. CP did show he was able to play Pac Man on the glass screen - something computer programmers call an "Easter Egg", where the Egg had been laid in the aircrafts systems not known (S-76C).
Honeywell specifies it is s stabilised antenna on this family of radars so without power, there is no stabilisation of the antenna and it will flop around on its gimbals.
Honeywell specifies it is s stabilised antenna on this family of radars so without power, there is no stabilisation of the antenna and it will flop around on its gimbals.
Maybe? According to an article from the manufacturer - The Use, And Misuse Of Weather Radar – Part 4 (https://aerospace.honeywell.com/us/en/about-us/blogs/radar-corner-weather-radar)
Honeywell Primus 880/660/440, Bendix King RDR-2000/2060/2100 and the Honeywell RDR-4000 and RDR-7000 systems. All of the radars just listed “except the RDR-4000” use stepper motors and it is safe to turn power off during taxi or any other phase of flight.
Stephen D. Hammack
Test Pilot, Flight Technical Services
Honeywell Aerospace Technologies
ShyTorque
22nd Jan 2024, 17:42
I got into the habit of leaving the radar on STBY so it came on as the relevant bus bar came on line. I was advised that ground taxying could be quite harmful if the unit was left unpowered.
casper64
22nd Jan 2024, 17:53
In Helionix equipped aircraft it will actually fail the automatic Pre-flight check which also checks the avionics including WX radar if installed.
Winnie
23rd Jan 2024, 01:13
Well it DOES talk to the MAU, so I suppose it is wise to keep on because of that too...
Cheers all!
Maybe? According to an article from the manufacturer - The Use, And Misuse Of Weather Radar – Part 4 (https://aerospace.honeywell.com/us/en/about-us/blogs/radar-corner-weather-radar)
Stephen D. Hammack
Test Pilot, Flight Technical Services
Honeywell Aerospace Technologies
Nice one RVDT - can't argue with the horse's mouth:ok: