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Question of the Month
 
 What is Mode S ?
 
 
Mode S is the new data transfer capability provided by aircraft transponders which respond to the Secondary Surveillance Radar (SSR) system used throughout the world.
 
Not all secondary surveillance radar heads are Mode S capable, for example, at the time of writing RAF Lyneham's SSR is not mode S capable.
 
When the SSR system began, there was a technological limit to the capability to use the radio bandwidth for transfer of data.  This limited the system to passing just the 4 digit squark code (Mode Alpha, which is similar to military mode 3), later Mode Charlie (Mode C) was added to the capability.  Mode C was the addition of altitude data to the transponder's response. 
 
Mode S is a hugely expanded capability to pass extra data. 
 
In the case of elementary fits (as found on some of the club aircraft - GTX330 and TT31 transponders), this is limited to the following 4 items of information:
 
- The Mode A four digit squark.
 
- The Mode C altitude data.
 
- A unique 24bit Mode S allocation (allocated by the Civil Aviation Authority at the time of aircraft registration - or in the case of older aircraft, allocated several years ago in preparation for mode S fitment).  This is used by ACAS II (TCAS) fitted aircraft to identify and communicate with each other.
 
- Callsign (as stated on Flight Plan) or Aircraft Registration (If no flight plan submitted).
 
 
Mode S Enhanced capability transmits substantially more information (for example - heading bug selection, altitude selected, aircraft speed, etc).  None of the club aircraft are fitted with Enhanced capability.
 
Additionally there is a capability called "ADS-B Out", this can then add more information for example aircraft position if connected to a suitable GPS receiver.  None of the club aircraft are transmitting ADS-B Out information, although both the GTX330 and TT31 have this capability once connected to a suitable GPS receiver.
 
 
 
 
 
 
 
 
 How much ice is acceptable on the aircraft on departure? 
 
 
None!  The question then is "How do I get all the ice off the aircraft?".  This is quite simple, and can be done in one of two ways:
 
Deicing
 
1.  If it is a sunny day then move the aircraft into the direct sunlight and wait.  This works better on G-WFFW and G-BNSP as they are a darker colour.
 
2.  Use a de-icing fluid.  Lyneham Flying Club provides Kilfrost RDF (rapid defrosting fluid).  The applicator is a garden spray pump system (stored in the POL locker with "Aircraft deicer" written on it).  If this runs out there is a plastic container with a Kilfrost RDF label on it, use this to replenish the spray system.  Spray this on the surfaces which have ice on them and wait about 10 minutes, then re-check to ensure there is no ice, if there is then re-treat with Kilfrost.
 
3.  Do not try to scrape ice off the surfaces (as you might with the windscreen of a car), it will seriously damage the paintwork.  Would you scrape ice off the paintwork of your car??  Probably not as this too would cause serious damage to your car's painwork.
 
 
 
PCAS. What is it? 
 
 
Portable Collision Avoidance System.
 
The two best known systems on the market are manufactured by Zaon Flight Systems and are designated Zaon MRX and Zaon XRX. 
 
The MRX is the smaller and less expensive unit and is about the size of an iPhone.  It can provide information on a single collision threat aircraft on its bright LED display (it will always display the highest threat aircraft information).  It will provide information on distance, vertical displacement and vertical trend of the threat aircraft.
 
The XRX is the larger, much more expensive system, which can display information about more aircraft, it can be integrated into other "glass screen" avionics and provides information on azimuth in addition to the distance and vertical displacement.
 
Both systems work by "listening" for the responses from aircraft transponders (while ignoring the host aircraft's transponder).  They then assess the strength of the signal (Mode A) to provide a range, next they compare the threat aircraft's transponder encoded altitude (Mode C) with the host aircraft's transponder encoded altitude and their own internal altimeter, to provide an accurate vertical displacement of the threat aircraft from the host aircraft.
 
More information can be found in the PCAS MRX manual. (Click Here)
 
 
 
 
 
Can a VFR Flight Plan be Filed Online? 
 
 
Yes.
 
The National Air Traffic Service (NATS) website will allow pilots to file a VFR flight plan online.  In order to control the service it is necessary to apply for a login, in doing so the NATS will check the pilots credentials and then issue a login.  All logins will be reviewed at regular intervals to ensure the system does not become overloaded with non-users, but no account will be cancelled without first contacting the registered user via the regisetered email.
 
Clued Up (the CAA safety magazine) provided a detailed description on how to use the site.  This can be downloaded here (How to use the NATS VFR Flightplan online system).
 
In order to get started go to www.flightplanningonline.co.uk and register by going to "Applying for an AFPEx Account" and then "Individual Application Form".
 
Oil Replenishment. How much oil should be put in the aircraft when refilling?
 
Warrior
The minimum oil allowed in the Warrior engine is 4 US quarts and the maximum is 8 US Quarts. 
 
Any more than 6 US quarts tends to get "blown overboard" by the engine and so filling above 6 US quarts is a waste of oil.  This is a recognised feature of Lycoming engines and each one has its own "Oil Level" down to which it will blow out oil, thereby wasting oil if it is filled above its own "Oil Level". In the case of these Warrior engines their oil levels are slightly above 6 US Quarts.
 
The club policy is to operate the Warriors' oil levels between 5 and 6 quarts.
 
The oil is provided by the aircraft owners in 1 US Quart bottles.
 
This means that the oil should only be replenished when the oil level gets down to 5 US quarts or below, and when this occurs a whole bottle should be added to the engine.  This will raise the level to 6 US quarts again (or in the case that the oil was below 5, it will still satisfy the requirement to be between 5 and 6 US quarts).
 
 
T67M-Mk2 Firefly (The yellow and black one)
The minimum oil allowed in the T67M-Mk2 Firefly engine is 4 US quarts and the maximum is 8 US Quarts. 
 
Any more than 7 US quarts tends to get "blown overboard" by the engine and so filling above 7 US quarts is a waste of oil.  This is a recognised feature of Lycoming engines and each one has its own "Oil Level" down to which it will blow out oil, thereby wasting oil if it is filled above its own "Oil Level". In the case of this T67M-Mk2 Firefly engine its oil level is 7 US Quarts.
 
The club policy is to operate the T67M-Mk2's oil levels between 6 and 7 quarts.
 
The oil is provided by the aircraft owners in 1 US Quart bottles.
 
This means that the oil should only be replenished when the oil level gets down to 6 US quarts or below, and when this occurs a whole bottle should be added to the engine.  This will raise the level to 7 US quarts again (or in the case that the oil was below 6, it will still satisfy the requirement to be between 6 and 7 US quarts).
 
 
Please don't put empty uncrushed bottles back into the cabinet as it leads us to believe there is more oil available than there actually is.  Please always crush the empty bottles before placing them in the required receptacle.
 
 
 
 
 
 

When do you use the "ON" button on the Garmin GTX330 Transponders?

The first part of this answer is "Never"!  If you use the "ON" function then you are only turning on the "Mode A" function of the unit, this means that ATC can see your position and Squark only, but do not get any altitude information.  By going from "STBY" to "ALT" you still turn the transponder on, but you activate it using "Mode A and C".  Mode C gives altitude information.
The only feasable situation where "ON" might be used is if ATC request that you "Turn off Mode Charlie".  It is not envisaged that ATC would ever give this kind of request.
 
So when should the unit be switched from "STBY" to "ALT"?  This should be done once you have been cleared onto the runway, and it should be switched back to "STBY" at the end of the trip during the after landing checks.
 
Happy Flying.
Garmin GTX330