Date: 202011
Local time of day: 0001-0600
Location: ZZZ.Airport, US
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
Reporter organization: Air Carrier
Reporter function: Flight Attendant (On Duty)
Reporter qualification: Flight Attendant Current
Human factors: Physiological - Other
Second reporter function: Flight Attendant In Charge; Flight Attendant (On Duty)
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor; Flight Deck / Cabin / Aircraft Event Illness / Injury
Detector: Person Flight Attendant
When detected: Pre-flight
Result: General Flight Cancelled / Delayed; General Release Refused / Aircraft Not Accepted; General Maintenance Action
Contributing factors: Aircraft; Human Factors; Environment - Non Weather Related
Primary problem: Aircraft

Narrative: Upon stepping aboard Aircraft X; I immediately detected an odor that had a burnt wire smell.  The other FA's also made comments such as; 'What is that smell? It smells like something is burning' as they stepped onboard.  I was the D FA and began checking my safety equipment.  I looked in the galley to see if any circuit breakers had popped and also looked in the oven to determine if the odor was from a forgotten burnt meal.  All circuits were in proper place and there was no food in oven.  I then walked down the aisle to determine if the burnt-wire smell was coming from the aft galley.  I stopped at Row 21; aircraft right and stepped up on Seat 21 D as the odor was very strong above the OH bin.  I could not visibly see any sign of smoke but the odor was quite strong.  I then walked back up to fwd galley as I saw that the Captain was beginning a briefing.  Captain stated that this aircraft had just come out of 'mothballs' and had just cleared a major inspection in State X.  He stated that it had just arrived to ZZZ and the Captain of that flight informed him that a smoke alarm for the aft cabin activated upon landing.  Captain stated that this happens from time to time and poses no threat of fire.  All of us 4 FAs told him that we smelled a burnt wire odor in the cabin.  A male individual; name unknown; representing Maintenance stated that we 'probably were smelling new carpet glue'.  Captain waited for the Maintenance personnel member to step off of the aircraft and then told us FA's that if we were not comfortable with the odor that he backed us and would insist that we fly a different aircraft to ZZZ1 or return to hotel if aircraft was not available.  All 4 of us FA's unanimously and instantly stated that we did not feel comfortable on this aircraft and we wanted to change aircraft in the interest of Safety First.  I then told the Captain that I noticed the odor was particularly strong by OH compartment of 21D.  We then walked to that row and Captain also noticed that it had a strong odor of either 'heated dust' or 'hot wire' on the lighting ballast.  He then asked me if I personally felt safe taking this aircraft. I told him that I am very safety minded and the odor was not normal or usual to me.  We all stayed in the first class seating area and continued personal conversations among us.  The Captain was not present as he was talking to Operations.  After approximately 15 minutes of remaining in the first class seating area; the other FAs noticed that my voice was getting hoarse and that I was beginning to lose my voice.   To the best of my recollection; I believe that C FA; and B FA; both stated that their throats felt scratchy.After approximately another 15 minutes of staying and waiting for a decision onboard; in the first class seating area; we were told by [the] Captain that we were changing into different aircraft for our flight back to ZZZ1.  We then deplaned the aircraft and walked to the other waiting aircraft.  My voice remained coarse for an additional 30 minutes and I developed a migraine during the boarding process.  I had the migraine the entire flight to ZZZ1; and it continued until early afternoon of date.  Additionally; I awoke on the morning of date with a sore and scratchy throat.  Both my migraine and scratchy throat subsided around 1400 hours on date.  I have had a continuous low-grade headache since date through present date.  I did not seek any medical attention as I 'normally' suffer from low grade sinus headaches regularly and use an OTC nasal spray along with Tylenol.I commend our Captain; for valuing and backing our decision to prioritize safety first.I would hope that Aircraft X was ferried back to ZZZ without full crew and guests in the pursuit of safety.


Second narrative: Upon crew boarding aircraft for return ZZZ-ZZZ1; [flight attendants] smelled what seemed like an electrical burning smell. It was not possible to find a fresh place of air on the plane; but the smell did seem worse as we walked further back. Our Pilots were met by that aircraft's ferrying pilots who also explained an aft lav smoke alarm went off while they were flying/descending after couple hours flight.The aircraft had just completed its mechanical run through after being 'unparked' from its holding location where it had been for 5 months. Unsure what that smell was; and given the circumstances of the aft lav smoke detector going off just previous to our boarding; our crew was offered another aircraft to take back to ZZZ1 which we accepted.At that point we had sat on the plane for likely about 30-45 minutes waiting for the phone calls and approvals and aircraft delay or swap or grounding decisions to be made. The flight attendants were in the cabin the whole time. Pilots came and left to discuss in jetway. Agents boarded for a couple of minutes and concurred on the smell immediately.Crew spoke of headaches; sore throat; and itchy/stuffy nose afterwards.  Just concerned for aircraft returning to operation after long time [of being] parked.


Synopsis: Flight attendants reported smelling a burning odor during boarding and experiencing health issues.