SCP Foundation

SCP-XXXX must be kept inside a 60m x 60m x 20m containment room.

Even though it's a jet plane, you still don't have to go through the exact dimensions of the room unless containment becomes compromised if the room is accidentally made 61x60x20. I would recommend replacing this with: "SCP-XXXX is to be kept inside a secure storage hanger." But there's also other parts of your beginning procedures so let's address those.

Room walls must be constructed with 6 layers of Titanium-Steel alloy and an inner core of Ceramic, insulating Polyurethane foam and ██████, in order to keep it pressure-insulated and completely soundproofed.

So I understand that the problems associated with your SCP come about from the rattling sound that kills people. I also understand that this sound is usually created by wind. That being said, these containment procedures seem a bit overzealous to counteract those effects. For example, the Foundation could instead chuck this thing underground and make sure no air currents get in. As per the soundproofing, I believe you can simply say that the room needs to be soundproofed and sealed to prevent airflow(I'm not sure about how pressurization affects wind-flow so I'd recommend explaining this briefly somewhere). This part of the procedures I'd recommend trimming this down and consolidating with the initial procedures. Consolidated, that might look like:

You'll notice I touch on audio recording which is part of the next chunk of your procedures.

The room must stay sealed and video surveilled, and a condition of vacuum must be maintained within the room at all times.

This part is unnecessary. The Foundation automatically keeps its property under surveillance. The vacuum can also be assumed to be perpetuated. The only reason to mention this would really be if the vacuum condition had to be turned on or off. So this part can be chucked out safely.

The room can be entered only through a depressurization chamber, all personnel accessing the room must wear special pressurized and soundproofed suits in order to survive into vacuum. Every authorized foundation researcher entering the room must wait during a 60 seconds depressurization process before accessing SCP-XXXX’s room.

Now you might wonder why I'm going to say most of this part can be cut out safely as well. It all has to do with implication and standard procedure. First off, since you've mentioned the presence of a vacuum, you can assume the Foundation is also going to naturally instruct its personnel on how to enter and exit a vacuum safely as well. The soundproof suits can be made into a brief aside because this IS necessary(the danger of sound is an added variable in your vacuum, but not one in most vacuums so it needs mention).

All Class D personnel must enter the room when vacuum condition is suspended.

If only D-Class personnel are allowed into the containment unit, state that. Because this reads that anyone who is not D-Class can enter the hanger/room when the vacuum condition is still being maintained. Remember, the more precise you are, the more implications arise.

Video surveillance devices must not record any sound that may be produced inside the containment room in the event of vacuum-sustaining systems failure.

Honestly I feel that audio recording would just be turned off completely at all times just to be safe.

As far as Special Containment Procedures go, I'd say you have a good grasp on what needs to be done to prevent the death noise, but you go a little overboard. The trimmed down version provided in the box covers the same bases as yours, and is general enough to account for every question that arose in your longer explanation. Also, it looks tighter.

SCP-XXXX looks like an average Lockheed L-1011 “Tristar” jet airliner.

Is SCP-XXXX not a Tristar jet airliner? Even if it has anomalous properties, the object doesn't actually change it's nature entirely. Also, since most jet-liners are production-line made, there's not really a reason to say "average." This can be tightened up into "SCP-XXXX is a Lockheed L-1011 "Tristar" jet airliner."

Its building date is estimated to be within 1972 and 1981.

Now you say there are no markings or callsigns on this plane so let's assume there's nothing indicating a date of manufacturing. Real life Tristars were manufactured from 1968-1984. That's it. The time frame is pretty close to what you have here and, since it doesn't really play a part in your story, I'd recommend cutting it out entirely. For example, if an anomaly is an iPhone 10, then I don't need to know it's approximate time of creation because there's already a time-frame of creation with the product.

It was found in a small corner of ██████ Airport

The first part has no clinical tone. I would recommend just stating that it was found in an airport in Greece, since you also appear interested in censoring which airport exactly. This saves the censor some time.

It appears to have no callsign or writings of any kind on its skin

What about inside? Many of the internal parts of airplanes are made by different companies who mark their products.

while its coloration pattern resembles the one used by ██████████████.

I don't really see how knowing the plane's coloration would cause a security breach. However, what I can tell you is that since effectively no information is conveyed here, this doesn't really need to be here.

On the inside every system seems to be broken due to the long period of inactivity and researchers had documented the complete lack of seats.

This sentence can be tidied up. I'd recommend instead using "SCP-XXXX is completely inoperable and shows signs of long-term abandonment. There are no seats inside."

The aircraft was found by airport personnel in a state of decay in 20██, presumably it had been staying in such a position for █ years.

This is bit of an immersion breaking line. How did this plane just sit on private property, with an active security staff, unnoticed for years? I'd be willing to buy that it suddenly appeared and only looks like it's been there for years, but the way this sentence is currently phrased makes the airport security look blind.

The details concerning its desertion are still unknown, but it probably happened due to its effects.

"It probably happened" has no clinical tone. Scientists don't make these statements. I would recommend instead using "it's theorized that this is due to blah blah blah."

SCP Foundation came into contact

Use "The Foundation" to sound more professional. Note, I capitalize "the" simply because it's the start of your sentence. This is usually not capitalized.

airport staff reported that most people in the airport and in the sorrounding area who came into close visual or hearing contact with the aircraft had begun to disappear, only to be found, several weeks later, deceased. After further investigation regarding the phenomena, the research team discovered the disappearances to be linked to a “tinkling” or “rattling” sound produced by the compressor blades inside the engines.

Surrounding is spelled wrong. Now the primary concern with this chunk is that it doesn't really explain how the airport staff were immune or how the Foundation nailed down this death epidemic's source in a rattling plane engine, without the loss of any Foundation personnel(since none are mentioned). However, we'll go over this in the concept check.

The sound is usually produced by wind entering the engines at slow speed, making them run slowly.

This sentence reads a bit awkwardly and is awfully alone despite it being a key mechanism of your SCP. I'd recommend integrating this into your description of effects and rephrasing it to sound more concise: "SCP-XXXX's anomalous sound is typically the result of air currents entering the engines and moving the internal parts."

The aircraft was later transported to Site ██, after a proper containment room had been constructed.

This is unnecessary as almost every SCP with really specific containment procedures is only transferred to its containment unit once it's been constructed or otherwise set up.

The rest of your article's description deals with the fact that people who listen to this rattling noise begin to suffer mental afflictions, hear the noise everywhere in an increasing volume, and eventually plop over dead. There are specific problems with this as a concept, so I will address the nature of thee in your concept check. I'm not ignoring the line-by-line analysis, but I feel that you'll be better able to use them once you revise the concept.

Furthermore, regardless of the location of the aircraft, presence of wind in the airport where it was found still affects the engines, also within the vacuum containment chamber.
However, if engine blades stay still in a condition of no wind upon the retrieval location, the sound doesn’t appear to manifest, therefore the aircraft produces no effects upon subjects

I will be honest, I think this sentence can be entirely cut out. I didn't understand it. So wind in the airport still reaches SCP-XXXX and turns the engines so sound/wind-proofing the room was unnecessary apparently. However, the airport wind doesn't make the machine components rattle, even though it's turning the blades, because the room is sound/wind-proofed. I don't think this adds anything really and would recommend cutting it.

Weather conditions in ██████ Airport must always be monitored.

This can be cut along with the previous chunk. But just know that this technically belongs in the containment procedures since it effects how SCP-XXXX's anomalous effects are contained.

exposition: 6

I think you mean "expedition."

PLEASE [ILLEGIBLE] THIS [ILLEGIBLE] STOP.

FIND A WAY TO END [ILLEGIBLE] AND [ILLEGIBLE] ME

THE SOUND [ILLEGIBLE] TOO LOUD

TO LOUD
TOO LOUD
HEL[ILLEGIBLE]

This didn't really add much. It's a garbled accounting of effects already described. If this was more coherent and descriptive, then it could sort of personify the effects you describe. However, as it is right now, the only thing most readers feel is that this D-Class thinks the sound is loud. I would recommend either cutting this, or cutting down on the incoherence and doubling down on the emotional pain conveyed through writing.

Although this message is clearly directed to the Foundation, subject D-4532 seemed to have been keeping this message whithin his sleeve, instead of handing it over. Subject D-4532 has been the only one to have produced a direct handwritten document about SCP-XXXX so far.

I don't really see the purpose of this. I feel like it's here to answer a question but, as a reader, I never found myself asking why there aren't any written accounts of SCP-XXXX's effects. I think this can be safely excised as well since otherwise it raises the question of "why does the Foundation think this is important for an executive summary of an SCP?" Also, 'within' is spelled incorrectly.

This is an airplane that makes a rattling sound. This rattling sound kills everyone who hears it.

This is not a summary of your SCP, this is a summary of your article. Right now, the effects of your SCP are a little bland and overdone. Objects that kill people like this aren't very interesting in of by themselves. They can be, if executed very very well and assisted by other narrative techniques. However, the only supplementary material provided is a garbled recounting of your SCP's effects. I would recommend taking this back to the ideas and brainstorming forum. There, the brainstorming whiz users can help you polish off your SCP's effects to be much more interesting on their own. They can also recommend and propose a variety of different stories, logs, interviews and other elements that can add flavor and story to your article.