Recommends FAA Require Checks Into MRA Internal Leakage

The National Transportation Safety Board (NTSB) has issued two recommendations that the FAA immediately require Sikorsky S-76 operators conduct immediate checks into leakage in the internal assemblies of the helicopters' main rotor actuators.

The NTSB's specific recommendations are as follows:

(Urgent A-05-33)

1. Conduct an immediate internal leakage test of all main rotor actuators with more than 500 hours since new and/or overhaul;
2. Conduct subsequent recurring tests at a period not to exceed 500 hours;
3. Report the test results to the Federal Aviation Administration and/or Sikorsky; and
4. Correct any problems as necessary.

(Urgent A-05-35)

The NTSB recommends the FAA require Sikorsky S-76 helicopter operators to:

1. Conduct immediate visual and laboratory examinations of hydraulic fluid and filter elements in hydraulic systems with actuators with more than 500 hours since new and/or overhaul for plasma flakes or other contamination that exceeds the manufacturers' allowable limits of concentration and size;
2. Conduct subsequent recurring tests at a period not to exceed 500 hours;
3. Report findings of contamination and flakes to the Federal Aviation Administration and/or Sikorsky and
4. Correct any problems as necessary.

The NTSB also recommends the FAA direct the principal operations inspectors of all Sikorsky S-76 helicopter operators to reemphasize the importance of, and requirement for, a preflight check of control movement smoothness and flight control 'stick-jump' at every engine start.

FMI: View the complete recommendation letter (PDF)