Airworthiness Directive · Amendment 39-17662 · Main rotor blades
Erickson Air-Crane Incorporated Helicopters (Type Certificate Previously Held by Sikorsky Aircraft Corporation)
This AD applies to Erickson Air-Crane Incorporated (Erickson) Model S-64E and S-64F helicopters, with rotary wing blade assembly (main rotor blade), part number 6415-20201-043, -045, -047, -048, -049, -050, or -051; or 6415-20601-041, -042, -043, -044, -045, -046, -047, -048, -049, -050, -051, or -052, installed, certificated in any category.
We are superseding airworthiness directive (AD) 90-26-12 for Sikorsky Aircraft Corporation (Sikorsky) Model S-64E helicopters. AD 90-26-12 required checks of the main rotor blades for a crack. This new AD retains the actions required by AD 90-26-12, reflects that the type certificate (TC) for this model helicopter has been transferred to Erickson Air-Crane Incorporated (Erickson), and expands the applicability to include the similar Erickson Model S-64F helicopters. This AD is prompted by a need to expand the applicability to include Model S-64F helicopters and clarify the applicable main rotor blades by part number. These actions are intended to detect a crack in the main rotor blade and prevent blade separation and subsequent loss of control of the helicopter.
You are responsible for performing each action required by this AD within the specified compliance time unless it has already been accomplished prior to that time.
(1) Before further flight, visually check the Blade Inspection Method (BIM) pressure indicators of the main rotor blades for a black or red color indication.
(2) Before further flight, replace any blade with a black or red color indication in a BIM pressure indicator with an airworthy part of the same part number unless the black or red color indication is determined to be the result of BIM system malfunction.
Note 1 to paragraph (f)(2) of this AD: Paragraphs (f)(4)(i-iv) of this AD specify how to determine if a BIM system is functioning correctly.
(3) Repeat the visual BIM pressure indicator check required by paragraph (f)(1) of this AD prior to the first flight of each day and thereafter at intervals not to exceed:
(i) Three hours time-in-service (TIS) from the last check for helicopters engaged in seven or more external lifts per hour; or
(ii) Five hours TIS from the last check for helicopters engaged in either less than seven external lifts per hour or operation without external cargo.
(4) Prior to the first flight of each day, check the BIM pressure indicator for proper function as follows:
(i) Press in and hold the manual test lever (grenade-type handle) on the raised area of the handle over the pin-type actuation plunger. Do not handle the indicator glass bulb since the heat of the hand may change the internal reference pressure and result in an erroneous indicator reading.
(ii) Depress the actuation plunger fully to shut off the pressure completely from the blade into the indicator. If necessary, press with the thumbs of both hands to overcome the plunger spring force.
Note 2 to paragraph (f)(4)(ii) of this AD: If pressure is applied to the end of the lever on the flat area, the actuation plunger will not fully depress.
(iii) Verify proper operation of the indicator by observing that a full-black or full-red (unsafe) indication appears in not less than 10 or more than 30 seconds after depressing the plunger for a temperature of 20 degrees F (−6.7 degrees C) or above. At lower temperatures, extend the upper limit to the corresponding time as follows:
(A) 19 to 0 degrees F (−7.2 to −17.8 degrees C); upper limit of 35 seconds.
(B) −1 to −20 degrees F (−18.3 to −28.9 degrees C); upper limit of 40 seconds.
(C) −21 to −40 degrees F (−29.4 to −40.0 degrees C); upper limit of 50 seconds.
(D) −41 to −60 degrees F (−40.5 to −51.1 degrees C); upper limit of 60 seconds.
(iv) Release the lever and observe that the black or red indication snaps back immediately, leaving an all-white or all-yellow (safe) indication.
(v) If the indicator does not meet the specified requirements, then either identify and correct the BIM indicator malfunction or replace the suspect main rotor blade with an airworthy blade of the same part number prior to further flight.
(5) The checks required by paragraphs (f)(1) and (f)(4)(i-iv) of this AD may be performed by the owner/operator (pilot) holding at least a private pilot certificate, and must be entered into the aircraft records showing compliance with this AD in accordance with 14 CFR §§ 43.9(a)(1)-(4) and 14 CFR 91.417(a)(2)(v). The record must be maintained as required by 14 CFR §§ 91.417, 121.380, or 135.439.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
