Help w/ terminology

[Mecaniquito84]

Hi:
on B767, Engine Ice Detection System, You may find on MEL referrences to: (30-80-01)

"ADVISORY" Ice detection system, and

"PRIMARY" Ice detection System.

I'm unable to find which is which. Any inputs and or references?

Rgds

[vapilot2004]

Advisory ice detection relies on TAT and visual identification of liquid water. It is up to the crew to take action based on the parameters and observations. This is considered 'the old and reliable' method.

Primary ice detection is automated and relies upon purpose-designed sensors and is a certificated system. These systems are typically quicker and better at detecting icing conditions than the aforementioned Advisory method, often doing so directly.

In reference to the MEL, you can typically go without Primary, but not Advisory Ice Detection equipment as the latter is considered the 'bare bones' fallback.

[Mecaniquito84]

Still not clear. MEL:

30-80-01 Ice Detection System
30-80-01-01 Advisory. CAT"D"

30-80-01 Ice Detection System
30-80-01-02 Primary. CAT "C"
May be inoperative provided alternate procedures are established and used.
OPERATIONS (O)
Pilot must manually operate anti-ice system when in icing conditions.
NOTE: The ICE DETECTORS message may display during takeoff if the
primary ice detection system is operated in the manual mode.

Any reference to MM?

Thanks

[Mecaniquito84]

We have here (big commercial) a Switch light & EICAS msg
??

[vapilot2004]

On many modern aircraft the Advisory system is also sensor based, while the Primary Ice Detection system is typically automated and will activate EAI and WAI as required with no input from the crew. What the MMEL says here is if your Primary is out, there must be SOP to mitigate the loss - eg, in this case, more involvement of the crew. The category gives you an idea of the implied necessity of the system involved, with D category getting more time to correct than C.

In either case, while the MMEL does not specify the obvious, the crew will revert to visual and TAT methods of ice detection, use forecast data and PIREPS, and activate AI as per their SOP.

[Intruder]

If set up like the 747, there are 2 possible ice detection possibilities. A Primary system is associated with Auto Anti-Ice on nacelles, wings, or both. An Advisory system does not have the automatic feature, so you must turn on the anti-ice yourself.

Icing Detection (Primary)
The icing detection system detects airplane icing conditions in flight. Two probes
on the forward fuselage and system logic:
• control nacelle and wing anti-icing valves,
• display anti-icing system operating indications on primary EICAS, and
• display EICAS alert messages

Icing Detection (Advisory)
The icing detection system detects airplane icing conditions in flight. A probe on
the left side of the forward fuselage and system logic:
• display anti-icing system operating indications on primary EICAS, and
• display EICAS alert messages