Twanda and Byron Jones did not specify what damages they believe they should receive in the wrongful death suit they filed Thursday in Philadelphia Common Pleas Court.
Their 11-year-old daughter, Abiah, was on a trip for honor-roll students when she fell about 150 feet from the Giant Wheel at Morey's Mariner's Landing Pier in Wildwood on June 3.
Investigators have not been able to determine how the girl, who was riding alone, got out of the gondola.
A state report found the ride's restraints to be working properly and suggested that to get out of the car, a passenger probably would have had to stand.
Though it doesn't offer a complete explanation of what may have happened, the girl's family does list factors that they say contributed to her fall. They blame wind - though details of how hard the wind may have been blowing were not given in the claim - and the ride's lack of restraints for causing the fall. They also say the ride operator was wrong to let her get on alone and that she was not adequately warned of the dangers.
In its report, the state Department of Community Affairs recommended a new rule forbidding children from riding alone in Ferris wheels.
The Giant Wheel has since reopened. Morey's now does not let passengers under 5 feet tall ride alone. When Abiah fell, the minimum height was 4 feet, 6 inches.
Soon after the state issued its preliminary report last month, Twanda and Byron Jones met with reporters in New York and Philadelphia with their then-lawyer, who was promising a broad investigation into Ferris wheel flaws. They said at the time that Ferris wheels should have more restraints.
And the lawyer, Larry Bendesky, said he was looking into whether anyone was responsible for the girl's death.
Since then, the couple has switched law firms.
Jeffrey Reiff, a lawyer at their new firm, said Friday that the Pleasantville, N.J., couple is suing in Pennsylvania court because Morey's Pier does extensive marketing there.
Morey's spokeswoman Lindsey Young, said the company would not comment.