Το ελικόπτερο προσγειώθηκε κοντά.

Because ελικόπτερο is a neuter noun in Greek, so it takes the neuter singular definite article το.

In this sentence:

• το = the
• ελικόπτερο = helicopter

Grammatically, το ελικόπτερο is in the nominative singular, because it is the subject of the sentence.

A useful comparison:

• ο = masculine singular the
• η = feminine singular the
• το = neuter singular the

Προσγειώθηκε is in the aorist, which is the most common Greek tense for a completed event in the past.

Here it means landed as a single whole action.

So:

• προσγειώνεται = it lands / it is landing
• προσγειώθηκε = it landed

Greek often uses the aorist where English uses the simple past.

That is a very common learner question.

The ending -θηκε is associated with the mediopassive / aorist passive pattern in Modern Greek. But forms like this are not always translated as passive English verbs.

Here, προσγειώθηκε means simply landed, not was landed.

Greek often uses this kind of form for actions that happen to the subject or that the subject undergoes as a complete event.

A helpful contrast:

• Ο πιλότος προσγείωσε το ελικόπτερο. = The pilot landed the helicopter.
• Το ελικόπτερο προσγειώθηκε. = The helicopter landed.

So in your sentence, the helicopter is not being described as an object of someone else’s action; Greek just uses this verb form for the intransitive idea land.

The dictionary form is usually προσγειώνομαι for the intransitive meaning to land.

So the pattern is roughly:

• προσγειώνομαι = I land
• προσγειώνεται = it lands / it is landing
• προσγειώθηκε = it landed

You may also see the related active verb προσγειώνω, which is used when someone lands something.

Here κοντά is an adverb. It means nearby / close by.

In this sentence it stands on its own, so it means something like nearby rather than near something specific.

Compare:

• Το ελικόπτερο προσγειώθηκε κοντά. = The helicopter landed nearby.
• Το ελικόπτερο προσγειώθηκε κοντά στο χωριό. = The helicopter landed near the village.

So κοντά can be used:

• by itself = nearby
• with a complement = near something, usually with σε / στο / στην etc.

No. Greek normally does not need a separate subject pronoun when the subject is clear.

In your sentence, the subject is already stated:

• Το ελικόπτερο

And the verb form προσγειώθηκε is also clearly 3rd person singular.

So Greek does not need an extra word for it. This is very normal in Greek.

Greek word order is more flexible than English, so yes, it can change.

The version you have is the most neutral and straightforward:

• Το ελικόπτερο προσγειώθηκε κοντά.

Other orders are possible, depending on emphasis, for example:

• Προσγειώθηκε κοντά το ελικόπτερο.

That can sound more marked or more context-dependent. For a learner, the original order is the safest default.

A rough English-style pronunciation is:

to e-LI-ko-pte-ro pros-yee-O-thi-ke ko-NDA

A few notes:

• ελικόπτερο has the stress on λί
• προσγειώθηκε has the stress on ώ
• κοντά has the stress on the last syllable

Also:

• θ sounds like th in think
• κοντά is often pronounced roughly kon-DA
• in προσγειώθηκε, the sound around γει is not exactly like English, but a rough yee / y sound is a useful approximation

The written accent marks in Greek show you where the stress goes.

Yes.

• Το ελικόπτερο = the helicopter
• Ένα ελικόπτερο = a helicopter

So:

• Ένα ελικόπτερο προσγειώθηκε κοντά. = A helicopter landed nearby.

Using το suggests that the helicopter is specific, known, or already identifiable from the context.

The plural is:

• τα ελικόπτερα = the helicopters

And the verb would also change to plural:

• Τα ελικόπτερα προσγειώθηκαν κοντά. = The helicopters landed nearby.

So:

• singular: το ελικόπτερο προσγειώθηκε
• plural: τα ελικόπτερα προσγειώθηκαν