2024-07-06 Houston Crash RCA

Owned by Smile Khatri
Last updated: 2024-07-07 by Yuchen Lin
3 min read

Update the title following the format: Jan 01, 2023 - RCA Name

1 Incident overview | 2  Executive summary | 3  Incident timeline | 4  Postmortem report | 5  Recommendations for future

Incident overview

Postmortem owner

@Yuchen Lin @Smile Khatri

Airframe

Houston

Related incidents

 

Incident date

Jul 6, 2024

Approx. Damage Costs

$2

Report Date

Jul 6, 2024

 Executive summary

When flying Houston, sometime it yaws and rolls unexpectedly without any RC input. This only happens once every while but it has a serious potential to damage on-board electronics and must be rectified.

 

 Incident timeline

2024-07-06 Houston Autonomy and EFS flight test A detailed summary of the timeline and recap are included in this document.

 Postmortem report

Instructions

Report

Instructions

Report

 Leadup

List the sequence of events that led to the incident.

  1. Arm, take off in loiter to 10m altitude.

  2. Roll forward via RC input.

  3. Drone loses control and rolls 180 degrees while descending. Disarm.

  4. Drone rolls 180 again as it lands roughly on the ground.

 Fault

Describe what didn't work as expected. If available, include relevant data visualizations.

Drone have unexpected flight behavior that is not even controllable in loiter.

Did run into a lot of prearm warning before the crash but the error does not appear when take off

 Detection

Report when the team detected the incident and how they knew it was happening. Describe how the team could've improved time to detection.

The timing for the crash and not understood well. Need to reserach more to understand what is there. Probably involve more testing and document.

 Response

Report who responded to the incident and describe what they did at what times. Include any delays or obstacles to responding.

PIC for the flight test respond. Disarm the drone after lose control authority.

 Recovery

Report how the user impact was mitigated and when the incident was deemed resolved. Describe how the team could've improved time to mitigation.

  • RCA the issue

  • Add into checklist

  • Impact analysis

Five whys root cause identification

Run a 5-whys analysis to understand the true causes of the incident.

  • EKF MAG0 failure.

  • Poor tuning. The last time Houston was tuned was 1 year ago. Since then, new electronics have been mounted. Disable mag0 before tuning it again.

Related records

Check if any past incidents could've had the same root cause. Note what mitigation was attempted in those incidents and ask why this incident occurred again.

 

image-20240706-211218.png
The Pitch input triggers a pitch and roll change (Note: roll input is after Roll changes)

 

 

image-20240707-003849.png
MAG plots

 

 

Suggesting to do auto tune and disable mag 0 since a lot of warning observed is MAG 0 realigned

 Lessons learned

Describe what you learned, what went well, and how you can improve.

 

 Recommendations for future

Actionable Recommendation

Reasoning

Actionable Recommendation

Reasoning