К трапу подошёл автобус, и пассажиры начали выходить по рядам.

Трап in this context means the mobile staircase leading to an airplane.

So к трапу means up to the aircraft stairs.

This word can have other meanings in other contexts, but at an airport it normally refers to the boarding stairs.

К normally takes the dative case, so:

• трап → nominative
• трапу → dative

So:

• к трапу = toward / up to the stairs

This is a very common pattern:

• к дому = to the house
• к двери = to the door
• к самолёту = to the airplane

Подойти means to come up to / approach.

So автобус подошёл к трапу literally means the bus came up to the stairs.

Even though a bus does not walk, Russian often uses подойти / подходить more broadly for something moving into position. In everyday speech, this is normal.

A more vehicle-specific verb like подъехал is also possible in many contexts, but подошёл emphasizes the idea of coming up to the stairs.

Because the subject is автобус, which is:

• masculine
• singular

In the past tense, Russian verbs agree with gender and number:

• подошёл = masculine singular
• подошла = feminine singular
• подошло = neuter singular
• подошли = plural

So автобус подошёл is correct.

Both are possible.

• Автобус подошёл к трапу...
• К трапу подошёл автобус...

Russian word order is more flexible than English word order. Here, putting к трапу first highlights where the bus came to.

So the sentence structure gives a slight scene-setting effect:

• К трапу подошёл автобус = Up to the stairs came a bus

This is natural Russian word order, especially in narration.

И simply means and. It connects the two parts of the sentence:

1. К трапу подошёл автобус
2. пассажиры начали выходить по рядам

So the sentence describes two linked events:

• the bus came up to the stairs,
• and the passengers began to get out row by row.

Because начали выходить means began to get out / started disembarking, which focuses on the beginning of the process.

• начали выходить = started getting out
• вышли = got out / exited

Using начали + infinitive is very common in Russian when you want to show that an action has just started.

So this sentence is not saying that all the passengers had already finished exiting. It says the process began.

After начать / начинать, Russian usually uses an imperfective infinitive, because the focus is on the process that starts.

So:

• начали выходить = began to be in the process of exiting

This is much more natural than начали выйти, which would sound wrong in standard Russian.

A useful rule of thumb:

• начать / начинать + imperfective infinitive

Examples:

• начал читать = started reading
• начала говорить = started speaking
• начали выходить = started exiting

По рядам means by rows or row by row.

It suggests that the passengers were leaving in an ordered sequence, not all at once.

Depending on context, a natural English translation could be:

• row by row
• in rows
• one row at a time

In this sentence, row by row is probably the best natural interpretation.

Here по takes the dative plural.

• singular: ряд
• dative plural: рядам

So:

• по рядам = by rows / according to rows / row by row

This use of по often expresses distribution or movement/action in units:

• по одному = one by one
• по очереди = in turn
• по группам = in groups
• по рядам = by rows

Grammatically, выходить just means to go out / get out / exit. The sentence itself does not explicitly say from where.

The context suggests airport movement near the plane stairs, so the intended meaning is probably something like disembarking in an orderly way. In real usage, Russian often leaves this unstated if the situation is clear.

If someone wanted to make it fully explicit, they could say:

• выходить из автобуса = get out of the bus
• выходить из самолёта = get out of the plane

But in this sentence, the source is understood from context.

Yes, indirectly.

Подойти is related to the motion-verb system. It is built from идти / ходить and means to approach / come up to. But at this stage, it is often best to learn подойти as a whole verb with the meaning come up to.

Likewise:

• подходить = imperfective
• подойти = perfective

In this sentence, подошёл is the past tense of the perfective verb подойти, showing a completed approach: the bus arrived up to the stairs.

There is a nice aspect contrast here:

• подошёл — perfective
• начали — perfective
• выходить — imperfective

Why?

• подошёл: the bus completed the action of approaching.
• начали: the passengers completed the action of starting.
• выходить: exiting is presented as a process that was underway.

So the sentence structure is roughly:

• one completed event happened,
• then another completed event of beginning happened,
• and that beginning led into an ongoing process.

You could do that to understand the structure, but it is not natural English.

A more natural English rendering would be:

• A bus pulled up to the stairs
• A bus came up to the aircraft stairs

So the Russian word order helps show emphasis, but you usually should not copy that word order directly into English.