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1. What is the life limit of the S-58T?
Unlike other helicopters and aircraft the airframe of the S-58T
has no life limit.
2. How many S-58T's were built?
There were 1,833 H34 / S-58's manufactured at Sikorsky Aircraft's facilities in the cities of Bridgeport and Stratford, both in the State of Connecticut. Approximately 150 of these H34 / S-58's were subsequently converted to the twin-turbine version S-58T, with the installation of the Pratt & Whitney PT6T Twin-Pac kit.
There were an additional 300 aircraft manufactured in other countries
under license from Sikorsky.
3. Can the S-58T be reliably supported?
Dangle Aviation and CHX specialize in the support of the S-58T,
and will offer worldwide support of this helicopter (spares, overhauls,
technical) for many years to come.
4. Can main rotor blades with honeycomb pockets be flown with blades with ribbed pockets?
Yes, the S1615-20201 (honeycomb pockets) and S1615-20301 (ribbed
pockets) are fully interchangeable, as long as the are similarly configured
(abrasion strips, etc.) and properly balanced.
5. I am told that the P/N RG17020B1 Fuel Boost Pump is no longer available. Is there a replacement?
A new type of fuel boost pump has received FAA approval for use
on the S-58T as a replacement for the RG17020B1. It's part number
is IHC-87, and it has proven to be most reliable. Overhauls for the
existing RG17020B1 pumps are still available.
6. I read that the cross-feed fuel system on the S-58T has a potentially serious problem. Can you tell me about it?
Yes, this is a problem which only effects S-58T's with the "Configuration II" type fuel system which is used on civilian aircraft. This problem does not effect the military "Configuration I" type fuel system, which is used on all aircraft operated by the Indonesian Air Force and the Royal Thai Air Force.
This problem on the "Configuration II" type system happens only when one fuel tank is empty (causing shut-down of one engine), and the cross-feed valve is open. This situation creates the possibility of fuel starvation to the other engine. The Flight Manual states not to operate without fuel in both tanks when the cross-feed is open.
More details on this potential problem can be obtained upon request by e-mailing our contact address.
Again, this problem DOES NOT effect the military "Configuration
I" type fuel system, used on the Indonesian Air Force and the Royal Thai
Air Force S-58T's.
7. We would like to avoid the necessity of making dye-penetrant checks every 50 hours on the star and 15-hour magnifying-glass inspection on the horns of our P/N S1610-20000-19 Main Rotor Heads. How can we avoid having to do this?
These inspections are required according to the S-58T Equalized
Inspection and Maintenance Program (SA4047-20) manual, and is because your
MRH has magnesium stars and horns. The easy way to eliminate these
labor-intensive inspections is to upgrade the Main Rotor Head to the S1610-20000-17
configuration. The -17 configuration includes the installation of
an aluminum stationary star and aluminum pitch horns, which eliminates
the star inspection, and increases the horn inspection to 150 hours.
8. When doing the servo check during ground run-up, the following occurs: When I shut off the aux servo, I get the normal "stick jump," but when I shut off the primary servos, I get a very rough condition and I can see that the blade tip path is not even close to what it should be. What causes this to happen?
When this happens, it is an indication that your main rotor blades are aerodynamically out of balance. The primary servo system will tend to mask this problem.
As this problem concerns the main rotor blades, an S-58T blade
repair specialist is the person to contact for help with this problem.
(As a service to our customers, Dangle/CHX will make this contact on your
behalf if requested.)
9. We are experiencing premature failure of the spline on the Angle Gear Box Hydraulic pump. What could cause this?
We feel this is due to insufficient lubrication, and is probably
caused by too infrequent greasing of the splines. Dangle/CHX recommend
checking the splines for wear and applying the proper grease as per the
S-58T Equalized Inspection and Maintenance Program (SA4047-20) manual,
except we recommend that it be done every 50 hours.
10. Where can I go for technical assistance on the S-58T?
This website is setup expressly for the purpose of providing technical support and assistance to all those involved with the S-58T helicopter, and particularly those military operators outside of the USA.
All you have to do is click on the "Contact" link, and send us your question. We will reply directly to you as soon as possible. We also welcome comments, greetings, stories, experiences or anything else our many friends worldwide would like to share with us or with other operators.
11. Where will new parts come from?
Several manufacturers obtained P.M.A.s on the key items.
12. Are S58Ts still available?
Yes, Good used and reconditioned aircraft are still on the market.
13. Is the S58T still a viable helicopter for logging?
Yes, There are no restrictions regarding logging with the S58T. The FAA requires the cycles be monitored and certain inspections to be performed at specified times.
14. What are the current fleets of S58Ts being used for?
A. Logging
B. Fire fighting
C. Law enforcement
D. Utility (air conditioners,
etc.)
E. Internal freight
F. Passengers
G. Military (in two countries)
H. Offshore oil
We look forward to hearing from you!