Audio Bug: Loud "Tick/Crackle" sound isolated to Default B737-800 on macOS (Aerofly FS 4)

Dear IPACS Team and Community,

I am experiencing a persistent and highly specific audio anomaly when using the default Boeing 737-800 in Aerofly FS 4 on macOS. The sound occurs regularly and randomly during all phases of flight (on the ground, taxiing, airborne and in cruise). Strangely enough, when I choose the Cold&Dark state, with not a single noise forthcoming from the aircraft, that peculiar 'crackle' sound is not present, which makes me firmly believe there is an issue with the audio-set in this particular aircraft.

The Issue

A loud, sharp "crackle" or "hard tick" sound is audible every so often. It likely is not a general system/hardware issue and more like an audio artifact within the aircraft's sound loop or configuration itself, specifically akin to a wave file clipping due to being too loud or an abrupt, incorrectly mixed loop point in the sound file data.

Crucial Observations

• Aircraft Specific: This issue is exclusively tied to the default B737-800.
• Other Aircraft Are Fine: I have extensively tested other default aircraft (A320, A350, A380, B777) and none exhibit this noise.
• System Specific: I am running on macOS Sequoia 15.7.3. I have confirmed there are no general audio issues with my operating system, hardware, or external audio equipment. The issue is contained entirely within the simulator when the 737 is loaded.
• Tests: I have confirmed this issue is consistent across multiple medium-haul test flights within the sim (WARR-WAAA, ENGM-LEPA, and LEMD-GCLP); in all three instances, the crackle noise occurred repeatedly at random intervals.

Troubleshooting Steps Already Performed

To help narrow down the cause and ensure this isn't a local configuration error, I have already taken the following steps on my macOS system without success:

1. Verified Integrity of Game Files: Used the Steam "Verify integrity of application files" function. All files were confirmed and validated.
2. Reset Game Configuration: Cleared the game's application support/configuration folder (~/Library/Containers/com.ipacs.aerofly.fs4/...) to force a fresh configuration setup.
3. Tested Different Audio Outputs: Confirmed the sound persists across different headphone sets and system outputs.

Request for Assistance

Given that this bug is isolated to a single aircraft model even after a clean configuration and file verification, I believe it points to an underlying issue within the B737-800's specific asset files or its sound programming logic within the current macOS build of Aerofly FS 4.

I am requesting that the developers investigate this specific sound package. A fix or guidance on how to manually locate and replace the offending sound file would be greatly appreciated.

Thank you for your time and assistance in resolving this immersion-breaking issue.

Sadly I can't confirm that, as I stayed inside the cockpit during all three flights.
It is something to heavily worry about, as it's heard constantly, the issue is consistent every time I use the default B737-800.

As said before: Given that this sound-bug is isolated to a single aircraft model even after a clean configuration and file verification, I believe it points to an underlying issue within the B737-800's specific asset files or its sound programming logic within the current macOS build of Aerofly FS 4.

I am requesting that the developers investigate this specific sound package. A fix or guidance on how to manually locate and replace the offending sound file would be greatly appreciated.

Thank you for your time and assistance in resolving this immersion-breaking issue.

I thank you for your input, but I would highly appreciate it if you could review the complete report I have provided, as it contains comprehensive details that address potential questions regarding this matter. I am confident that this points directly to a sound bug in this package.

My goal is for this report to be evaluated directly by the IPACS Development team so they can investigate this specific sound package.
Hereby I would like to focus the replies back on-topic and stay away from any deviated answers that do not assist in fully understanding and resolving this audio issue.

Thanks in advance to the IPACS Team for their time and assistance in resolving this matter which negatively impacts user immersion.

Hi Jan,

Thank you very much for your feedback.

I thought initially that it was with the APU on only, but I started the flight up today with the GPU only, and indeed with the packs on, I hear the 'crackle noise' every so often. I will try to record this 'crackle noise' (knackendes geräusch) somehow as best as possible, as it is truly weird and even scary. (It sounds like a tick from an old vinyl with dust in the grooves, but really loud, like it ticks through the speakers. As it involves a digital sound or a multiple sound layering issue, I assume it is more like a clipping noise / sound loop noise from one of the audios in the cockpit of the 737.)

I will however these next few days test it as you suggested:
- I'll perform a ground startup in the 737-900ER too and let you know what happens.
- I'll perform a ground startup in the 737-500 too and let you know what happens.

Thank you in advance for your time and assistance.

Hi Jan,

I have now completed the additional tests you suggested on the other aircraft variants:

• 737-900ER: The exact same 'crackle noise' appears as soon as the packs are set to ON from a cold & dark state with the GPU connected.
• 737-500: The exact same 'crackle noise' appears as soon as the packs are set to ON from a cold & dark state with the GPU connected.

To consolidate my findings and confirm the scenario across all tested aircraft in the fleet: This sound-issue seems linked to the activation of the packs, regardless of the specific aircraft model. (-800, -900ER, or -500) It could perhaps hint at another cockpit sound, but it can't be a coincidence.

I can sit for hours with the GPU (Ground Power Unit) on the ground, and the audio environment is clean. However, the moment the packs are switched to the ON position, the very loud 'crackle noise' begins at very random intervals. This strongly reinforces my initial assumption that it is a digital sound or multiple sound layering issue specifically tied to the packs' sound file or activation trigger, likely a clipping noise or sound loop issue.

I am actively performing training flights now, but recording the specific noise remains a priority. I will get to that as soon as practically possible to provide you with an audio sample.

Thank you very much in advance for your time in investigating this matter.

Hi Jan,

See the full specs in my signature I'm currently on MacOS 15.7.3 on my MacBook Pro.
(I do not trust MacOS Tahoe as of yet, as it contains still too many bugs, problems and issues. Until at least MacOS 26.5 I will not update)

Thank you very much in advance for your time in investigating this matter.