quote:

Originally posted by bigwagon:

quote:

Originally posted by JALLEN:


There is a data plate riveted to the airframe, usually on one side near the tail. There is an airworthiness certificate inside, a piece of paper displayed on one wall of the interior. Both of those must be in the plane in operation.

With those, though, all other parts are replaceable.

When Cessna stopped building single engine airplanes in the mid-80s, those became pretty valuable. I have seen 172s in airworthy condition, built from parts of an unknown number of different airplanes.

They buy wrecks, salvage parts, get a data plate and certificate, and rivet and bolt and wire enough parts together, a wing, a wing spar, cabin, instrument panel, tail surfaces, instruments, engine, etc., to get a working airplane that meets specs.

Interesting. So are the Airworthiness Certificate serial numbered to a specific airplane or are they just a designation that a particular model type has been certified as airworthy if built to a defined set of specs?

When built and maintained to spec, I think. Every part is replaceable, in theory if not in economic terms. Every part is certified, so you can’t just use any old bolts and nuts. But you can buy cowlings from other planes, engine mounts, windscreens, panels, fuel caps, horizontal stabilizers, all the other doodads and hinkery-doos, rivet them all together, sign it off and fly away.

I doubt any data plate has gone on a plane where none of the parts of the plane that left the factory with that data plate has been done as it doesn't seem economic, but maybe. If you have the logs, document eveything, an IA signs it off, you are good to go, as I understand it.

I looked at a couple where almost everything had been replaced. In effect, 3 or 4 wrecks had been cannibalized to make one good one, I think.

Actually, people can, and do build airplanes and engines around dataplates, in which the only existing piece of the original IS the data plate.

quote:

Originally posted by bigwagon:
Interesting. So are the Airworthiness Certificate serial numbered to a specific airplane or are they just a designation that a particular model type has been certified as airworthy if built to a defined set of specs?

The airworthiness certificate belongs with the airplane, to a specific serial number, and is in effect, a "birth certificate." Experimental airplanes built by individuals, or "homebuilts," also have airworthiness certificates. Airworthiness certificates also spell out the requirements to remain airworthy; a production, type-certificated airplane from a manufacturer will need to remain in conformity with it's type certification and be in a condition safe for flight, or the airworthiness is invalidated.

Also accompanying the airworthiness certificate in the airplane must be the registration, similar to a car registration, which is specific to the owner or organization that will be responsible for maintaining the aircraft in an airworthy condition.

Man that is terrible. Airplanes are just things that can be replaced but losing 2 lives, that just sucks.

Nearly all mishaps are preventable; the aviation community recognizes the loss of life, but the focus necessarily is on what can be learned from the event.

At the preliminary stage, there is often more speculation than fact, and while we do a lot of what-if in aviation, guesswork about what's happened isn't productive.

What is known is that the citation was landing when struck by the 150. The landing aircraft has the right of way. It's unlikely that the 150 pilot attempted to squeeze out as the citation was landing, and very likely that the 150 pilot was unaware of the citation. The citation pilot has indicated that he was unaware of the 150.

See and avoid is a regulatory requirement for all operations in all conditions...but it only works if one sees the other traffic. The citation pilot indicated he looked for traffic and did not see it, listened on the radio, and checked his TCAS. The reasons that he did not see, hear, or detect the 150 are unknown.

The actions of the 150 pilot are unknown, except that it's clear the 150 pilot initiated a takeoff, OR entered the runway environment at the time the Citation was landing. The FAA considers all runway crossings as critical, whether taking off or taxiing, and has made runway incursions an ongoing hot topic for a number of years now. It continues to be a critical issue.

I look at the runway like the barrel of a loaded firearm. When given a line-up-and-wait clearance, it's critical to check not only the approach area to the runway, but any crossing points downrange, as well as traffic in the air. Any time spend on the runway increases the time a change can occur and the potential for an incursion.

Most professional flight crews use Jeppesen charts, and Jepp puts "hot spots" on the airport diagram showing areas where critical points of convergence exist on an airport, either taxiways, or taxiway-runway. These are red circles, and are part of every takeoff and landing briefing. At smaller airports these are not depicted in many cases, but any place runways cross, or taxiways cross runways, should be considered potentially critical, as this event demonstrates.

quote:

Originally posted by bigwagon:
are the Airworthiness Certificate serial numbered to a specific airplane or are they just a designation that a particular model type has been certified as airworthy if built to a defined set of specs?

The Airworthiness Certificate goes with a specific airplane serial number.

The "designation that a particular model type has been certified as airworthy if built to a defined set of specs" is a Type Certificate.

So, the Type Certificate is basically authorization for the factory to build airplanes according to a set of specs.

Each individual airplane, when built in accordance with the Type Certificate, gets a serial number and an Airworthiness Certificate.

Throwing something else in the mix: Somebody might come up with a modification to the Type Certificate. Say, for example, an engine swap, for performance gain (that's just an example). They go through a process with the FAA and obtain approval for an STC -- a Supplementary Type Certificate.

I used the example of an engine upgrade, but it could be something almost trivial. Example: The V-Tail's Type Certificate specified that the battery installed would be a Gill (that's a brand of aviation battery). Another brand, Concorde, packs more punch in the same physical size. You can install a Concorde battery in place of the Gill, but to do it legally, you have to have a copy of the STC that was developed by Concorde.

Some vendors will just give the STC away when you buy their hardware. Other vendors will sell the STC for whatever they want to charge for it.

I needed several STCs for the V-Tail. Off the top of my head, I recall the battery swap, and also a change of autopilot, from the Century I that came with it, replaced by a more capable S-TEC autopilot.