As demonstrated previously, adjectives can be used as adverbs in German (Unit 4, Unit 6). When participial adjectives or adverbs are involved, it is common to see an adverb modifying an adjective, which can extend the complexity within a noun phrase.
das schnell steigende Flugzeug
the rapidly climbing airplane
das siedend heiße Wasser
the boiling-hot water
ein hart gekochtes Ei
the hard-boiled egg
die gestern gekochten Eier
the eggs boiled yesterday
mein brauner, schon gepackter Koffer
my brown suitcase, already packed
These complex noun phrases are a good opportunity to see the value in first marking off where each noun phrase begins and ends before attempting to translate a long sentence. It simplifies your task to know that everything inside a noun phrase can only be modifying the noun, not anything outside of the noun phrase. Remember that you can easily see which are adverbs and which are adjectives by simply noting which have adjective endings and which do not.