Monday, December 20, 2021

Quad City Challenger II, N778H: Accident occurred September 11, 2021 at Presque Isle County Airport (KPZQ), Rogers City, Michigan

This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed. 

The National Transportation Safety Board did not travel to the scene of this accident. 

Additional Participating Entity:
Federal Aviation Administration / Flight Standards District Office; Grand Rapids, Michigan
Location: Rogers City, Michigan
Accident Number: CEN21LA420
Date and Time: September 11, 2021, 07:45 Local
Registration: N778H
Aircraft: Quad City Ultralight Challenger II
Injuries: 1 Minor
Flight Conducted Under: Part 91: General aviation - Personal

On September 11, 2021, about 0745 eastern daylight time, a Quad City Ultralight Challenger II experimental airplane, N778H, was substantially damaged when it was involved in an accident near Rogers City, Michigan. The pilot sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.

The uncertificated pilot reported that about 100 ft into the takeoff roll on runway 27 the airplane began to swerve right, but before he could abort the takeoff he heard a bang and the airplane pitched up and rolled.

A witness reported that the airplane abruptly pitched up, rolled right, and impacted the ground in a left wing down attitude. The witness stated that the airplane had completed about 270° of right roll when the left wing impacted the ground.

Examination of the airplane revealed that the right wing's forward lift strut had separated from the fuselage longeron (Image 1). The channel bracket remained attached to the lift strut, but the AN4-24A bolt had pulled out of the fuselage longeron (Image 2). The ¼” AN365-248 nyloc nut that normally secured the AN4-24A bolt was not located during the investigation.

The pilot did not maintain maintenance records for the airplane, nor had the airplane undergone a condition inspection since the experimental airworthiness certificate was approved in 2007.

Aircraft and Owner/Operator Information

Aircraft Make: Quad City Ultralight
Registration: N778H
Model/Series: Challenger II NO SERIES
Aircraft Category: Airplane
Amateur Built:
Operator: On file 
Operating Certificate(s) Held: None
Operator Designator Code:

Meteorological Information and Flight Plan

Conditions at Accident Site: VMC 
Condition of Light: Day
Observation Facility, Elevation: KPZQ,670 ft msl 
Observation Time: 07:35 Local
Distance from Accident Site: 0 Nautical Miles
Temperature/Dew Point: 15°C /13°C
Lowest Cloud Condition:
Wind Speed/Gusts, Direction: 9 knots / , 200°
Lowest Ceiling: Overcast / 10000 ft AGL 
Visibility: 10 miles
Altimeter Setting: 29.89 inches Hg
Type of Flight Plan Filed: None
Departure Point: Rogers City, MI 
Destination: Rogers City, MI

Wreckage and Impact Information

Crew Injuries: 1 Minor 
Aircraft Damage: Substantial
Passenger Injuries: 
Aircraft Fire: None
Ground Injuries: 
Aircraft Explosion: None
Total Injuries: 1 Minor 
Latitude, Longitude: 45.407083,-83.812861 (est)


  1. Why didn't the design use a castle nut there? Seems flight critical, obviously.

  2. Did that bolt break at the threads, or does it appear that the nut “backed off”?

  3. A nylon locknut is used there, and typically you look for at least a thread or two showing past the locknut, as is normal practice. The bolt/nut is loaded in tension and incredibly strong. It's hard to believe the locknut stripped unless it wasn't completely tightened

    1. On the other hand, they can strip or snap when over-tightened.

  4. This is a well known issue with the challenger for years, check out other accident reports. They even sell a fix for the poor design.

    1. yes, but the "fix" doesn't "fix" it. I had one. The "fix" just cascades the failure point down the line so to speak. This design is non-fixable without a new fuselage.

  5. poor design. Quad City? You own this noobie mistake. Nobody designs a critical attachment point in that manner. For decades, you have tried to brush this under carpet.

  6. Placement of a critical lifting component with a single 1/4 inch bolt in TENSION is a big NO NO in aeronautical design. Engineering on Quad City products like the Challenger II has always been subpar, with no real upgrades despite knowing they had an issue from the get go. Quad City has never wanted to admit any responsibility. Just look at the track record on these planes. Ever wonder why so cheap on Trade a Plane or Barnstormers? All in all, a poor design that should be grounded immediately.

  7. A well known issue with this model. And they sell a "fix" for it? Why wasn't a recall done? But then again the last paragraph of the report is all you need to see.
    For crying out loud, maintenence and thorough inspections are...sheesh,does it even need to be said?

  8. Rony bracket strut retention failure saw renewed interest after a 2018 crash in Canada prompted an advisory to perform recurring removals for inspection. Aware owners should already be up to speed on that issue.

    Even though the preliminary report says no condition inspection of this bird was done, Rony bracket remove/reinstall cycles for inspection could have precipitated this failure due to re-use of the locknut or an assembly error.

    As noted by earlier comments, bad design to use single fastener in tension. Design change should have been made when crashes first started from fatigue cycling of the Rony brackets due to over-tightening the cross bolt that retains the strut to the bracket.

    The 2018 cracked bracket crash in Canada that renewed awareness:

    Official 2019 Transport Canada's inspection recommendation:

    NTSB report, 2007 cracked bracket wing-off crash, pilot saved by BRS:

    A 2010 crash with cracked brackets noted in docket:
    Lab report from docket with photos:

    If you know someone involved with one of these machines, share the KR link to this accident with them.