Requirement to test flight instruments

[Ayecapt]

Hi. Read in another thread a bit of banter about accessing CTA and the need to have calibrated flight instruments only if flying into CTA....... Well heres a extract from Raaus tech manual.

 

SECTION 12.4

 

 

INSTRUMENT & TRANSPONDER CHECKS

 

1 AIRCRAFT OPERATING IN CONTROLLED AIRSPACE (CTA) – CLASS C, D, E,

 

1. 1.1 Aircra that are currently legally permi ed to y in Controlled Airspace (CTA) as detailed in provisions of CAO 95.10, 95.32 or 95.55, must have their instruments maintained in accordance with the provisions of CAO 100.5. The checks are only available through a LAME with specialised calibrated equipment and appropriate licence ra ngs.
    
    
    
    
   
2. 1.2 Compass “swinging” is not mandatory, however, CASA AWB 34-008 provides good advice. A compass devia on card should be ed following any compass checking.
    
    
    
    
   
3. 1.3 Compliance with the required checks must be noted in the aircra log book.
    
    
    
   

 

 

2 AIRCRAFT OPERATING ONLY OUTSIDE CONTROLLED AIRSPACE (OCTA) – CLASS G

 

1. 2.1 Al meters must be checked every 2 years against a currently cer ed al meter (a LAMEs test equipment) or other appropriate test equipment (e.g. a water manometer and scale, or GPS) and must not deviate by more than +/- 100 feet, up to the maximum normally expected operating altude of the aircra .
    
    
    
    
   
2. 2.2 Airspeed indicators must be checked every 2 years against a manometer or against a GPS using test runs in opposite direc ons; and airspeed indica ons shall not vary by +/- 5kts; and
    
    
    
   

 

 

...........And so on. I wonder if these checks are being done every 2 years?

 

 

[Old Koreelah]

A timely reminder, Ayecapt. Easy enough to do. I have a simple manometer glued to the wall next to my plane.

 

For those of us who stay in G space, resetting Alt. to airport elevation before each flight and checking against GPS readings in flight should keep you well inside these requirements.

 

It's easy to fly extended squares to check the ASI against a couple of GPS units.

 

 

[FlyingVizsla]

For my plane, I do mine through a LAME as part of my maintenance - I'm NVFR etc.

 

RAA outside CTA, I suspect pilots do check their airspeed & altitude against their GPS, but don't put it in their aircraft log books. A manometer is easy to construct and the maths just a little more complicated.

 

A reminder to write it in the log book.

 

 

[Deskpilot]

As I restore my Thruster, I have wondered about the instruments that came with it. I decided to do a couple of tests.

 

First, the ASI. hooked it up to a pitot tube and fitted same to my car. As the instrument reads in mph, it was easy to do a conversion for set speeds. Luckily I have a nice long motorway nearby.

 

Whilst the gauge worked, my test wasn't conclusive due to the pitot being too near to the car and was effected by pressure waves from the slipstream. I 'm fairly sure it will be ok in still air.

 

As for my Altitude gauge, I simply looked up the height of my home on Street View in Google Earth (406feet), set the gauge and took a drive in to the hills. Mount Lofty, the highest point overlooking Adelaide is 2,385feet and the gauge read true at it's summit.

 

 

 

[skippydiesel]

....................................................................First, the ASI. hooked it up to a pitot tube and fitted same to my car. As the instrument reads in mph, it was easy to do a conversion for set speeds.

As for my Altitude gauge, I simply looked up the height of my home on Street View in Google Earth (406feet), set the gauge and took a drive in to the hills. Mount Lofty, the highest point overlooking Adelaide is 2,385feet and the gauge read true at it's summit.

Hi Deskpilot - most (I would be tempted to say all) car speedometers overread ie at 100 kph indicated your actual could be doing anywhere from 90-95 kph. Simple reason's for this -

 

• Car makers do not want to be complicit in speeding offenses, that is the defendant saying to the court I must have been under the speed limit your honour, because my speedo said I was doing 99 kph in a 100kph zone..
   
   
  
• The rolling diameter of tyres will change with tyre make/mode and pressure. A substantial margin is built in to your speedo, calibration to accommodate these variables.
   
   
  

 

 

Urban mythology has it that highway patrol cars have their speedo's calibrated to actual speed. This may be a hangover from the pre radar days when cops would use a range of measures to conclude a driver was speeding.

 

 

[Yenn]

A better way to do a rough test of ASI and altimeter is to connect a tube to the instrument and have water in a U bend. Check the reading at different heads of water. You can do positive heights for ASI and negative heights for altimeter. This is only rough as the required compliance with CAO 100.5 requires calibrated test equipment.

 

I just had my RV4 done at Redcliffe, including the transponder. Took a couple of hours and I was quoted $200 base, plus extra if anything needed attention, which my transponder did. havn't got the bill yet, but it was an easy process.

 

 

[planesmaker]

Desk pilot, your altimeter may well be working correctly but is the subscale correct? This needs to be adjusted from time to time.

 

 

[facthunter]

People, the GPS height has nothing to do with what an altimeter in good order and calibrated correctly, will read. An altimeter is calibrated to a (invented, but agreed ) standard atmosphere. Your GPS is more accurate, but that's too bad. All separation is based on altimeter readings. Perhaps that (one day ) will change, but that hasn't happened yet. Your (tested) altimeter is set to the appropriate QNH, below 10,000 feet (transition level) and above that to 1013.2 millibars or whatever it's called these days. and that's what you adhere to for your approved / chosen, cruise levels Nev

 

 

[Old Koreelah]

Interesting Nev, but how far out is the GPS method likely to be? I believe our Alt. must be within 100'.

 

 

[Ayecapt]

A timely reminder, Ayecapt. Easy enough to do. I have a simple manometer glued to the wall next to my plane.For those of us who stay in G space, resetting Alt. to airport elevation before each flight and checking against GPS readings in flight should keep you well inside these requirements.

It's easy to fly extended squares to check the ASI against a couple of GPS units.

Thanks for the reply. I recently suspected that our airspeed indicator was reading LOW . After a bit of checking i found a tee piece in the line that fed air from the rear of the ASI to the airswitch to be cracked . So faults do happen even in simple tube systems.

 

How do you lower the pressure on the open end of your manometer to test the altimeter? Is a big syringe suitable to pull air out . And i was wondering how big a manometer to build? Im guessing to use 16mm dia clear hose about 2 metres long before bending? Or is that too long?

 

Regards Brian

 

 

[pmccarthy]

if you search manometer it is described in other threads.

 

 

[Old Koreelah]

With water levels at least Capt, size doesn't matter much. I use a 7mm vinyl tube. (Food grade vinyl, I tested it full of AvGas in the sun for a year or so- no problem.) I got my instructions off the net (or this site, I can't remember) and used a tube about 3m long. Food colouring in the water makes it easier to see.

 

You're no doubt aware that you can easily destroy your instruments during this testing; their innards are very sensitive. I've connected a tube to my pitot head and given it the lightest cheek puff- the needle went to the end of the scale.

 

 

[facthunter]

OK, you don't compare it with the GPS officially (unless something has changed.) The GPS is mainly a position referencing instrument, but of course that could be expanded. The check can be done at an airport where the known height of your position is available reliably and using the ATIS QNH. The ARP (Aerodrome Reference Point) height is published and someone may have a way of establishing other heights around the place ie heights at each runway end are often available. The important thing where separation from each other is required we all use the same reference and this currently requires a sound knowledge of altimetry and a calibrated altimeter operating within required limits and using required settings on the Kollsman scale. Nev

 

 

[aro]

The geometry of the satellite system means that GPS altitude measurement is much less reliable than the horizontal position.

 

 

[Deskpilot]

Desk pilot, your altimeter may well be working correctly but is the subscale correct? This needs to be adjusted from time to time.

My altimeter is very old and doesn't have a subscale. The adjustment is by turning the dial face to your local height.

 

 

[turboplanner]

My altimeter is very old and doesn't have a subscale. The adjustment is by turning the dial face to your local height.

Unless you can dial in the QNH, you won't be in synch with the aircraft around you. The QNH can vary from hour to hour, and as Facthunter said is not related to gps height. It's more important that everyone is in the circuit at an indicated 1000 feet, than one being the exact measured distance, because while dimensionally more correct, he may be flying lower or higher than all other aircraft flying on the location's QNH.

 

 

[KRviator]

My altimeter is very old and doesn't have a subscale. The adjustment is by turning the dial face to your local height.

Then your aircraft is not compliant with CAO20.18 that requires a subscale settable in millibars.

[Deskpilot]

Thanks for the heads up guys. Now, anyone got a compliant gauge they're not using?

 

 

[KRviator]

Mendelshhon's have them but you're looking around $700-800 for a new one.

 

 

[facthunter]

That would be Chinese. (what isn't). Repair an old "other" one? Nev

 

 

[M61A1]

Then your aircraft is not compliant with CAO20.18 that requires a subscale settable in millibars.

Not necessarily....it depends on the aircraft.

 

 

[Deskpilot]

Not necessarily....it depends on the aircraft.

Care to elaborate mate.

 

 

[M61A1]

well. first read CAO 20.18 - 3.4

 

Other aircraft in private, aerial work or charter operations

 

 

 

3.4 Subject to paragraph 3A.3, an aircraft:

 

 

 

(a) engaged in a private, aerial work or charter operation; and

 

 

 

(b) not mentioned in paragraphs 3.1 to 3.3;

 

 

 

may only be operated under the V.F.R. if it is equipped with the following:

 

 

 

© the instruments specified in Appendix I;

 

 

 

(d) any other instruments and indicators specified in the aircraft’s flight manual.

 

 

Then 3A.3 as refered to above...

 

 

3A.3 Paragraph 3.4 does not apply to any other aircraft that operates under the V.F.R.:

 

 

 

(a) being an aircraft for which a current certificate of airworthiness as an LSA has been issued; or

 

 

 

(b) being an aircraft for which an experimental certificate has been issued under paragraph 21.191 (g), (h) or (j) or an LSA for which an experimental certificate has been issued under paragraph 21.191 (k), of CASR 1998;

 

if equipment is carried that provides a pilot with the same information that would be obtained by compliance with the requirements of Appendix I for operations by day, or Appendix IV if approved for operations by night.

 

Then go to CASR 21.191 as referred to above...

 

CIVIL AVIATION SAFETY REGULATIONS 1998 - REG 21.191

 

 

 

Experimental certificates

 

An experimental certificate may be issued for one or more of the following purposes:

 

 

 

(a) research and development: for example testing new aircraft design concepts, new aircraft equipment, new aircraft installations, new aircraft operating techniques, or new uses for aircraft;

 

 

 

(b) showing compliance with regulations: for example conducting flight tests and other operations to show compliance with the airworthiness regulations including flights to show compliance for issue of type and supplemental type certificates, flights to substantiate major design changes, and flights to show compliance with the function and reliability requirements of the regulations;

 

 

 

© training the applicant's flight crew;

 

 

 

(d) exhibition: for example exhibiting the aircraft's flight capabilities, performance, or unusual characteristics at air shows, motion picture, television, and similar productions, and the maintenance of exhibition flight proficiency, including (for persons exhibiting aircraft) flying to and from such air shows and productions;

 

 

 

(e) air racing: for example participating in air races, including (for participants) practising for air races and flying to and from racing events;

 

 

 

(f) market surveys: for example use of aircraft for purposes of conducting market surveys, sales demonstrations, and customer crew training only as provided in regulation 21.195;

 

 

 

(g) operating an amateur-built aircraft: that is an aircraft the major portion of which has been fabricated and assembled by a person who undertook the construction project solely for the person's own education or recreation;

 

(h) operating a kit-built aircraft: that is an aircraft in the primary category that meets the criteria of paragraph 21.024(1)(a) and that was assembled by a person from a kit manufactured by the holder of a production certificate for that kit, without the supervision and quality control of the production certificate holder under subregulation 21.184(1);

 

(i) private operations of prototype aircraft previously certificated under paragraph 21.191(a), (b) or (d);

 

 

 

(j) operating a light sport aircraft that:

 

 

 

(i) has been assembled from a kit in relation to which the applicant can give the information, statement and documents required by paragraph 21.193(e); and

 

 

 

(ii) has been assembled in accordance with the kit manufacturer's instructions for assembling the aircraft; and

 

 

 

(iii) is of the same make and model as a production aircraft covered by regulation 21.186 that has been issued with a special certificate of airworthiness;

 

(k) operating any other light sport aircraft covered by regulation 21.186 for which a special certificate of airworthiness for light sport aircraft, or another document of similar effect under a law of a Contracting State, has been issued.

 

 

[Deskpilot]

Thankyou my friend but this early in the morning it is a s clear as mud for me. I'll do some deeper reading when I'm fully awake.

 

 

[facthunter]

CASR's are not written for "normal" people. It's a Regulation written by lawyers for lawyers. Nev