But why is TB21 different? Which primary instrument they needed that 700 wouldn’t offer?
No idea. It could be that they just didn’t get around to doing it. Or it could be that while a non-turbo plane needs only a CHT instrument (no EGT instrument is needed), a turbo plane does need a TIT (turbo inlet temp) instrument because with a turbo you can get too high an EGT. Turbo installations are punishing for the engine because you can be running at max EGT for 75% power (say 1600F) and be doing it at FL150-200 where the air is only half as effective for cooling the engine (cylinders and the oil cooler). The lower OAT helps only a little because the real drop is only small in absolute (Kelvin) terms. So maybe that changed the certification requirements…
But also the DGAC can have weird requirements. They e.g. required that Socata locate the flow totaliser transducer on the pilot side of the firewall, despite the fact that it created a 20-30% error (due to turbulent flow) 
Of course Socata complied and sold the planes, with a smile. Only on an N-reg can this be legally fixed.
Paperwork rules!
But clearly there is far more latitude for an aircraft mfg to certify stuff under their TC than you can do as a 3rd party on an aftermarket STC. A TC holder gets lots of delegated powers to certify in-house, whereas an STC applicant has to prove absolutely everything (well, in paper terms, not necessarily functionally 
).
I thought about TIT, but 700/ 711 has it (711 is primary for TIT).
Ad last paragraph: Exactly.
Perhaps the 711 was not around in 2000 when Socata were doing that work.
As I wrote, 700 should not be primary (well, at least using JPI STC). Not for TIT, not for CHT. And yet it is in TB20. So why would they suddenly care? This is moot, but I’m scratching my head, so to speak.
An aircraft manufacturer, Part 145, Part 21, in-house DER if in the USA, in bed with its national CAA as they all are (to varying degrees), can take a seat out of a Mk 2 Ford Cortina and certify it
They can pick up any components made by e.g. an outfit which makes bits for homebuilts, certify it, and install it in a certified aircraft. Most major parts which GA aircraft mfgs buy-in (say landing gear pumps, hydraulic parts, electrical parts like switches) they buy in uncertified but with a CofC (a sham but necessary piece of paper) and this is a huge revenue generator, continuing way past the production life of the aircraft. It also keeps costs down.
So if say an EDM700 does/did not have a “primary” STC is irrelevant, if they certify it under their TC. Same with dual Garmin GNS installations – another big one.
You mean stuck closed?
Stuck open is the normal failure mode with a fully mechanical pressure capsule. You lose power at altitude, but the engine does not blow-up at the worst possible moment.
Arne wrote:
You mean stuck closed?
From the report:
The equivalent wire from the throttle position sensor that was found damaged on the aircraft, was then shorted to earth. This resulted in the orange warning light flashing and the servo motor being driven to the 100% position (nominally resulting in the wastegate being fully closed), and remaining there for as long as the wire was grounded.
This is an electronic engine control system.
My plane experienced propulsion related ‘issues’ resulting from (in my case) a bad ground lug connection on an electronic control unit power circuit, which despite redundant ground wires interrupted power occasionally depending on ambient temperature. Scary stuff when it occurs sporadically in flight, in my case much limiting engine power delivery. Finding it in the hangar took a long time until testing coincided with random, temporary failure of electrical continuity.
achimha wrote:
I’ve done baffle work, sealed every gap with RTV
Would anyone kindly tell me what RTV is in this respect? @achimha? @Peter? Is this some form of self-adhesive tape?
I have some holes in my baffles, which are intentionally there, they are for inserting the ratchet when pulling the spark plugs. I just wanted to temporarily close them in order to see how it affects cooling air flow. Or maybe I can use aluminum tape here?
RTV is Room-Temperature-Vulcanizing meaning it is single-component and sets without oven curing.
Household silicone sealant would be one type, although it releases acetic acid when curing , which can cause corrosion on unprotected aluminum
Better use some of the aerospace stuff to seal baffling, I use Dow Corning #736 for this application
