В отсутствие межевого плана площадь участка не проверили.

В отсутствие means in the absence of or with ... unavailable / missing.

So В отсутствие межевого плана means something like:

• In the absence of a boundary plan
• Since there was no boundary plan available

Compared with без, it sounds more formal and bureaucratic. In official Russian, в отсутствие is very common.

• без межевого плана = plain without a boundary plan
• в отсутствие межевого плана = more official, more like in the absence of the boundary plan

So the sentence has a legal/administrative tone.

Because в отсутствие is followed by the genitive case.

The dictionary form is:

• межевой план = boundary plan / land-survey plan

After в отсутствие, it changes to genitive singular:

• межевого плана

This pattern is normal:

• в отсутствие документа
• в отсутствие доказательств
• в отсутствие разрешения

So межевого плана is there because of the phrase в отсутствие.

Межевой план is a technical/legal term. It refers to an official land-survey document that describes a plot of land, especially its boundaries, measurements, and related cadastral information.

For a learner, the important point is that this is not everyday vocabulary. It belongs to legal, cadastral, or property-registration language.

Here площадь is the direct object of проверили, so it is in the accusative case.

But the form looks the same as the nominative:

• nominative: площадь
• accusative: площадь

That happens because площадь is an inanimate feminine noun of the third declension, and in the singular its nominative and accusative are identical.

So in this sentence:

• площадь участка = the area of the plot
• whole phrase = the thing that was not checked

Because площадь участка literally means the area of the plot.

Russian often uses the genitive for this kind of relationship:

• площадь участка = area of the plot
• граница участка = boundary of the plot
• владелец участка = owner of the plot

So участка depends on площадь and answers of what?

Russian often omits the subject when it is unknown, unimportant, or obvious from context.

So не проверили literally means:

• they did not check

But it often functions like English:

• it was not checked
• they didn’t check it

This is a very common Russian pattern, especially when the speaker does not want to name who did the action.

Because Russian commonly uses 3rd person plural with no stated subject to mean an indefinite agent:

• Сказали, что... = They said that... / It was said that...
• Меня не предупредили. = They didn’t warn me. / I wasn’t warned.
• Площадь участка не проверили. = They didn’t check the plot’s area. / The plot’s area was not checked.

So the plural does not mean we know there were several people. It is just the normal Russian way to express an unspecified they.

This is about aspect.

• проверили = perfective
• проверяли = imperfective

Here не проверили suggests that a specific expected check did not happen. It refers to a completed event that failed to take place.

So it has the sense:

• they did not carry out the check
• the area was not checked

If you said не проверяли, it would sound more like:

• they were not checking it
• they did not check it in general / repeatedly / as a process

In this sentence, the perfective проверили fits best because it sounds like one concrete verification that should have been done.

Yes. That would also be correct.

The difference is mostly stylistic:

• Площадь участка не проверили = active form with an unspecified they
• Площадь участка не была проверена = explicit passive

The version with не проверили is very natural in Russian and often sounds less heavy than the full passive. Russian uses this indefinite-plural construction much more freely than English does.

The word order puts the circumstance/reason first:

• В отсутствие межевого плана = under those conditions / because that document was missing

That frames the whole sentence before telling us what happened.

Then:

• площадь участка = what was not checked
• не проверили = the action

Russian word order is flexible, and this order sounds natural in official writing because it foregrounds the condition first.

A different order is possible, for example:

• Площадь участка не проверили в отсутствие межевого плана

But the original version sounds more formal and better organized for bureaucratic style.

They are close, but not exactly identical.

• в отсутствие = in the absence of, often referring to the actual situation in a particular case
• при отсутствии = if there is no... / when ... is absent, often sounding more procedural or rule-like

So:

• В отсутствие межевого плана площадь участка не проверили
  = in this case, because the plan was absent, they did not check the area

• При отсутствии межевого плана площадь участка не проверяют
  = if there is no plan, they do not check the area

So при отсутствии is especially common in instructions, regulations, and general rules.

It is natural, but it sounds formal and administrative, not conversational.

That is because of words like:

• в отсутствие
• межевой план

In everyday speech, a person might say something simpler, for example:

• Без межевого плана площадь участка не проверили.
• Не смогли проверить площадь участка без межевого плана.

So the original sentence is perfectly normal, but it belongs more to official, legal, or technical Russian than to casual conversation.