Narrative:

When the flight attendants first boarded the aircraft; in ZZZ; there was a strong musty odor. FA1 told the captain; who said it was not something to be concerned. The odor persisted until we reached cruising altitude then went away. It returned when we started descending in ZZZ1. When we arrived at the gate; the smell was very strong: musty; like when you first turn on an oxygen bottle; but much more pungent. When we arrived at the gate; it was really strong. FA1 went outside of the jetway; to get some air. The ZZZ1 cleaners said they smelled the smoke when they first entered the jetway. The gate agent said she smelled it; too. To her; it smelled like a crayon which was burning. The captain smelled and thought it might have been coming from the air conditioner. He said to tell him if it persisted. The odor lingered after take off; until after we reached 10;000 feet; then it dissipated. It returned again; as we started descending in phl. The captain wrote it up. FA1 felt a little lightheaded.fixing the air conditioner or ventilation system before putting the aircraft back in service.

Google
 

Original NASA ASRS Text

Title: A319 Flight Attendant reported an intermittent fume event during initial preflight until the completion of two flight segments.

Narrative: When the flight attendants first boarded the aircraft; in ZZZ; there was a strong musty odor. FA1 told the Captain; who said it was not something to be concerned. The odor persisted until we reached cruising altitude then went away. It returned when we started descending in ZZZ1. When we arrived at the gate; the smell was very strong: musty; like when you first turn on an oxygen bottle; but much more pungent. When we arrived at the gate; it was really strong. FA1 went outside of the jetway; to get some air. The ZZZ1 cleaners said they smelled the smoke when they first entered the jetway. The gate agent said she smelled it; too. To her; it smelled like a crayon which was burning. The Captain smelled and thought it might have been coming from the air conditioner. He said to tell him if it persisted. The odor lingered after take off; until after we reached 10;000 feet; then it dissipated. It returned again; as we started descending in PHL. The Captain wrote it up. FA1 felt a little lightheaded.Fixing the air conditioner or ventilation system before putting the aircraft back in service.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.