## Facts

- David Swann, an IBM employee, was injured while attempting to board an elevator in an office building in Rockville, Maryland when the elevator allegedly failed to level with the floor.
- The building was owned by Prudential Insurance Co. of America, managed by Carey Winston Company, and leased to IBM.
- Elevator number two was manufactured, installed, and exclusively maintained by Dover Elevator Company.
- Swann sued, alleging negligence and defects in the design, manufacture, installation, and maintenance of the elevator and sought substantial damages.
- At trial, Swann presented expert testimony identifying specific mechanical components and maintenance failures said to have caused the misleveling.
- The trial court instructed the jury on ordinary negligence but refused to give a res ipsa loquitur instruction.
- The jury returned a verdict for all defendants.

## Issues

1. Whether a plaintiff who introduces direct, specific evidence of the cause of an accident may also rely on res ipsa loquitur to establish negligence.
2. Whether the trial court erred in refusing a res ipsa loquitur jury instruction and, if so, whether any error was harmless.

## Decision

- The Court of Appeals of Maryland held that Swann could not rely on res ipsa loquitur because he offered direct evidence of the specific cause of the elevator’s misleveling through expert testimony.
- The trial court therefore did not err in refusing to instruct the jury on res ipsa loquitur.
- The intermediate appellate court’s contrary ruling was reversed, reinstating the defense verdict.

## Legal Principles

- Res ipsa loquitur is an evidentiary doctrine permitting, but not requiring, an inference of negligence when the cause of an accident is unknown and direct proof is unavailable.
- A plaintiff who offers direct evidence explaining how and why the accident occurred generally may not also submit the case on res ipsa loquitur.
- When a malfunction involves technical machinery outside common knowledge, expert testimony may be necessary to prove negligence; once the plaintiff supplies a specific expert causation theory, res ipsa’s substitute function is not available.
- A res ipsa loquitur instruction is improper when the plaintiff’s own proof identifies a specific causal mechanism for the injury.

## Conclusion

The court limited the use of res ipsa loquitur in Maryland by holding that a plaintiff who presents detailed expert proof of a specific cause of an accident cannot also seek a res ipsa inference, and it affirmed the trial court’s refusal to give a res ipsa instruction, reinstating the jury’s verdict for the elevator company.


Dover Elevator Co. v. Swann, 334 Md. 231, 638 A.2d 762 (1994)