Ohne Leiter kommen wir nicht an die obere Lampe im Flur.

German often puts something other than the subject in the first position to set the scene or emphasize it.

Here, Ohne Leiter is placed first to highlight the condition: without a ladder.

Even when something else comes first, the finite verb still has to stay in second position in a normal main clause. So:

• Ohne Leiter = position 1
• kommen = position 2
• wir = then the subject comes after the verb

That is why it is:

• Ohne Leiter kommen wir nicht ...

and not:

• Ohne Leiter wir kommen nicht ...

Ohne always takes the accusative case.

So if you use an article, you would say:

• ohne eine Leiter

In your sentence, the noun appears without an article:

• ohne Leiter

But the preposition itself still requires accusative.

Both can be possible, but they feel slightly different.

• ohne eine Leiter = more explicit, clearly without a ladder
• ohne Leiter = more general, more like without ladder / without any ladder available

German sometimes omits the article when talking about something in a general, non-specific way, especially in everyday speech.

So:

• Ohne eine Leiter kommen wir nicht ... = fully explicit
• Ohne Leiter kommen wir nicht ... = a bit more compact and idiomatic

Yes. Leiter can also mean leader, director, or manager depending on context.

For example:

• der Leiter der Schule = the head of the school

But in this sentence, because of Lampe and im Flur, it clearly means ladder. The context tells you we are talking about physically reaching something high up.

Here, an die Lampe kommen means to reach the lamp.

It does not mean simply to come to the lamp in the English sense. This is a common German way to express being able to physically get to something, especially with the idea of reaching it by hand or getting access to it.

So:

• Wir kommen nicht an die Lampe. = We can’t reach the lamp.

A close alternative would be:

• Wir erreichen die Lampe nicht.

But an die Lampe kommen sounds very natural in everyday German.

With the idea of reaching something physically, German often uses an.

• an etwas kommen = to get to / reach something

Using zu would sound different. zu often means movement toward a person or place, not necessarily physically reaching an object with your hand.

So in this sentence:

• an die Lampe kommen = reach the lamp

That is the natural choice here.

Yes. After an in this sentence, you have the accusative because there is an idea of movement toward the object: getting up to it, reaching it.

The noun is die Lampe, which is feminine. In the accusative singular, feminine stays die.

So:

• nominative: die Lampe
• accusative: die Lampe

That is why you get:

• an die obere Lampe

Because the adjective has a weak ending after the definite article die, and with a feminine singular noun in the accusative, that ending is -e.

So:

• die obere Lampe

not

• die oberen Lampe

The full structure is:

• die = definite article
• obere = adjective with weak ending
• Lampe = feminine noun

This is a very common question.

• obere = upper
• oberste = topmost / highest

So die obere Lampe means the lamp that is higher up, or the upper lamp.
Die oberste Lampe would mean the very highest lamp of all.

If there are two lamps, die obere Lampe is very natural.
If there are several levels and you mean the one at the very top, die oberste Lampe would be more precise.

In this sentence, nicht negates the idea of being able to reach the lamp.

• Ohne Leiter kommen wir nicht an die obere Lampe im Flur.

Here, nicht comes before the part that completes the idea of the verb phrase, namely an die obere Lampe im Flur.

In natural English terms, the sentence means:

• Without a ladder, we can’t reach the upper lamp in the hallway.

If you move nicht, the emphasis can change, so its position matters.

Im is a contraction of:

• in dem

So:

• im Flur = in the hallway / in the corridor

Because this is a location and not movement into the hallway, German uses the dative here.

So the full form would be:

• in dem Flur

but im Flur is the normal contracted form.

German often uses kommen an in this kind of everyday statement instead of saying can reach directly.

So:

• Wir kommen nicht an die Lampe. = We can’t reach the lamp.

A sentence with können is also possible:

• Ohne Leiter können wir die obere Lampe im Flur nicht erreichen.

That version is a bit more direct and slightly more formal in tone.
The original sentence sounds very natural and conversational.