Next questions

[Pengineer]

1.Aerials are painted with neoprene for...
A)Insulation
B)Erosion protection
C)To guard against P static

2.In a HF system the ATU tunes the aerial to
a) half a wavelenght
b) a quarter wavelenght
c) A wavelenght

3.The ATU tunes to achieve
a) 50ohms and a VSWR of 1:1
b) 50ohms and a VSWR of 1:3
c).........

4.HIRF
a)over a wide frequency range
b)over a narrow frequency range
c)only when the A/C txs on HF

Any suggestions?

[GoodToGo!]

At a guess, B,B,A and what the hell is HIRF?


Hope it helps, and someone please put me right if I am wrong!

Cheers

GTG! :D

[wryly smiling]

HIRF=High intensity radio frequency or something along those lines.
I would guess at B :confused:

[Pengineer]

Sorry its not HIRF, I cnat remember exactly what the question said, but its something to do with static noise and another question says its minimised by ensuring you have all your static wicks.
Its H**F I completely forget the acronym, sorry

[Pengineer]

Does the ATU not tune to exact wavelenght then?
Is a VSWR of 1:1 possible?

[Diablo]

High Intensity Radiated Field

[Pengineer]

Thats the stuff!


.....and the answers?

http://www.stopstart.fsnet.co.uk/Gif/scoob.gif

[Pengineer]

Is ther a difference between HIRF and static noise? one question I've seen is something like...
The effects of HIRF can be minimised by ensuring....
A) you have all your static wicks in good condition
B) you have all your bonding leads in good condition
C)?????

Any clues please?

[Pengineer]

So where are all the radio blokes when you need them? this reminds me of my days in BA!


http://www.stopstart.fsnet.co.uk/mica/FarSKid.gif

[gas path]

(1)HIRF means High Intensity Radiated Fields.

(2)HIRF/Lightning tasks in this section (AMM TASK 05-51-19-210-801 p201) are for scheduled maintenance.

(3)The purpose of the HIRF/Lightning inspections is to inspect wire bundle connectors for problems.

(4)The purpose of the HIRF/Lightning tasks is not to look along the lengths of the wire bundles.

(a) If you notice damage along the length of a wire bundle, make a note of the damage and do the necessary repairs after you complete the HIRF/Lightning inspection tasks.

(5)The inspections are applicable to the critical and essential systems and LRUs

NOTE:The emphasis of the HIRF/Lightning inspections is in the areas outside of the pressure vessel and in the Main Equipment Center. These areas are where HIRF/Lightning protection for systems is most important. If HIRF/Lightning protection problems exist, these are the areas where HIRF/Lightning protection will most likely be compromised. There may be systems listed in the following list which may not be inspected in any of the HIRF/Lightning inspections. This is because such systems may not have wire bundle connectors outside of the pressure vessel or in the Main Equipment Center.

Extract from AMM for 777
Broken down into Critical and Essential tasks

[ 21 August 2001: Message edited by: gas path ]

[Pengineer]

Thanks Gas Path for the information, is this something thats really only become important on the new electric jets?
and as regards the question is it bonding leads or static wicks?
Thanks for your patience.
ps type slowly I'm a slow reader.

I was rather hoping for some input from Blacksheep, he usually knows everything!
http://www.stopstart.fsnet.co.uk/Gif/magg.gif

[gas path]

Pengineer
To be honest I'd never heard of it until the cripple 7 came along, and certainly the first few a/c were done by a boeing crew.
The extract from an AMM had a lengthy list of the critical and then essential items that were inspected and from what I can remember no dismantling of conectors is required.(Unless a defect is found.)
Just a guess here but it must be something to do with the bonding of the connectors etc.

[The hippy]

pulling at the old grey matter!!!

Static noise can be produced by the build up of static on the fuslage in flight, dischargeing into the airflow. Reduced by static wicks that have a finite ohmic value, which allow the charge to bleed off the aircraft skin with out sparks (even small static sparks cause radio interference).
HIRF is lightning and reqires good bonding to allow the charge to run to the extremities, so that again the dischargers again can bleed the enduced charge off the aircraft. HIRF covers a large bandwith.

HOME PROJECT!
short out a 9V battery near a radio then by a tV

[ 23 August 2001: Message edited by: The hippy ]