Airworthiness Directives (AD)
Page Last Updated: 27 March 2013
FAA Aircraft Certification Service. (Link to FAA AD web site)
MD900 Helicopters (MDHI compiled list)
MD369/500/600 Helicopters (MDHI compiled list)
AD's applicable to MD Helicopters Aircraft
A listing of Airworthiness Directives, applicable to the various models of MD Helicopters aircraft, are provide as a service to our customers. The FAA is the primary authority concerning Airworthiness Directives.
The Airworthiness Directives below were collected from various FAA sources;
1) Summary of Airworthiness Directives for Small Aircraft and Rotorcraft
- Book 1 (AD's issued prior to 1980),
- Book 2 (AD's issued from 1980 through 1989),
- Book 3 (AD's issued from 1990 through 1996),
2) Biweekly Supplements
3) FAA web site
Disclaimer : Although we are attempting to provide accurate, current and complete information, we offer no warranty, express or implied regarding the accuracy, currency or completeness of the information included or linked. If you find any problems with the formatting of the data, please contact MDHI Publications . If you find any inaccuracies in content, please contact the originator of the document (normally identified at end of the document).
| AD Number | Subject |
| 2013-06-51 | This EAD has owners and operators do a cable conditioning lift, a load inspection test, deactivate or replace a hoist that fails the load inspection test, and record the results of the load inspection test on the component history card (or equivalent record). This EAD is in response to a rescue hoist that lost the ability to hold a maximum capacity load, which caused the test load to fall to the ground. |
| 2013-03-03 | This AD has owners and operators find the cure date for each NOTAR fan blade tension-torsion strap, make a calendar-time retirement life for some straps, reduce the retirement life of some straps, have each strap identified with the expiration date, and creates a component record card for each strap. Over time, moisture can reduce the strength of a strap. This AD is to prevent strap failures, loss of directional control, and subsequent loss of control of the rotorcraft. |
| 2012-21-01 | This amendment supersedes AD 2011-14-05 for MDHI Model MD900 helicopters. That AD currently requires a visual inspection, and if necessary, an eddy current inspection of the lower hub for a crack. If there is a crack, the AD requires replacing the lower hub with an airworthy lower hub. This superseding AD will require the same inspections as the existing AD but will also require long-term recurring inspections and replacing the lower hub with an airworthy lower hub. We are issuing this AD to detect a crack in the lower hub and prevent failure of the lower hub and subsequent loss of control of the helicopter. |
| 2011-22-08 | This amendment supersedes AD 2008-22-53 for MDHI Model MD900 helicopters. That AD currently requires turning ON both VSCS switches and turning OFF the autopilot (AP/SAS) switch; the removal of certain AP/SAS circuit breakers, the installation of a placard near the AP/SAS master switch and an airspeed limitation placard on the instrument panel, and revision of the RFM. This admendment keeps those requirements and gives an optional replacement of each applicable tube adapter with a new design tube adapter that will provide an end action for the unsafe condition. The necessary actions of this AD are intended to prevent the loss of yaw control and the subsequent loss of control of the helicopter. |
| 2011-14-05 | This amendment supersedes an existing airworthiness directive (AD) for MD Helicopters, Inc. (MDHI) Model MD900 helicopters. That AD currently requires visually inspecting the main rotor lower hub assembly (lower hub) for a crack, and if you find a crack, before further flight, replacing the unairworthy lower hub with an airworthy lower hub. Additionally, within 10 days of finding a cracked lower hub, the existing AD requires reporting the finding to the Los Angeles Aircraft Certification Office (LAACO). That AD was prompted by two reports of cracks detected in the hub in the area near the flex beam bolt hole locations during maintenance on two MDHI Model MD900 helicopters. |
| 2010-18-52 | Applicability: Model MD900 rotorcraft with lower main rotor hub (PNs 900R2101008-103/-105/-107) installed. Issued to detect a crack in the hub and to prevent failure of the hub and subsequent loss of control of the rotorcraft. Compliance: (a) Examine hub within 4 hours time-in-service for a crack with a careful inspection of the area adjacent to the 5 flex beam bolt hole locations; (b) If a crack is found, report this to the FAA with 10 days. (Supercedes FAA AD 2010-18-51.) |
| 2010-06-06 | Applicability: Model MD900 helicopters that currently require applying serial numbers to certain parts, increasing the life limit for various parts, maintaintng a previously established life limit for a certain vertical stabilizer control system (VSCS) bellcrank assembly and bellcrank arm, and correcting the part number for the VSCS bellcrank arm. Compliance: (a) Remove from service nonrotating swashplate assembly (PN 900C2010192-105, -107, -109, or -111) on or before 1800 hours time-in-service (TIS); collective drive link assembly (PN 900C2010207-101) on or before 3307 hours TIS; swashplate spherical slider bearing (PN 900C3010042-103) on or before 700 hours TIS; and VSCS bellcrank assembly (PN 900FP341712-103 and 9002341712-101) on or before 2700 hours TIS. (b) For SN 000002 to 000012 put the appropriate SN on the mid-forward truss assembly (PN 900F2401200-102), forward deck-fitting assembly (PN 900F2401500-103); and aft deck-fitting assembly (PN 900F2410600-103); and for SNs 000002 to 000048 put the appropriate SN on the left VSCS bellcrank assembly (PN 900F2341712-101), right VSCS bellcrank assembly (PN 900FP341712-103), and mid-aft truss strut assembly (PN 900F2401300-103). (Supercedes FAA AD 99-16-13 ) |
| 2009-07-13 | Applicability: Model MD900 (including MD902 Configuration) helicopters that have not complied with MD Helicopters, Inc. (MDHI) Mandatory Service Bulletin SB900-099 R1, dated December 27, 2006, certificated in any category. Compliance: Required as indicated, unless accomplished previously. To prevent loss of directional control of the helicopter, accomplish the following: (a) Within 30 days, reduce the gross weight limit to a maximum gross weight limit of 5,400 pounds by inserting a copy of this AD into the Limitations section of the Rotorcraft Flight Manual. |
| 2008-22-53fr | This superseding Emergency Airworthiness Directive (EAD) is prompted by 4 occurrences on the MD900 helicopters with failed left Vertical Stabilizer Control System (VSCS) adapter tubes where the vertical stabilizer became uncontrollable, resulting in reduced yaw control of the helicopter. There were no injuries, but in one occurrence, due to the high speed quick yaw, the helicopter lost a window and a door. The actions specified by this EAD are intended to prevent a reduction of yaw control and subsequent loss of control of the helicopter. (AMOC) |
| 2008-22-52 | This superseding Airworthiness Directive (AD) is prompted by several occurrences of failed adapter tubes. These incidents occurred on the MD900 helicopter Vertical Stabilizer Control System (VSCS); however, the same adapter tubes are used on 500N and 600N helicopter Yaw Stability Augmentation System (YSAS). We are issuing this EAD to prevent a reduction of yaw control and subsequent loss of control of the helicopter. |
| 2008-17-51 | This Emergency Airworthiness Directive (AD) is prompted by three reports of in-flight failure of the forward directional control cable (control cable) and loss of yaw control resulting in emergency landings and subsequent damage to the MD900 helicopters. On November 14, 2007, one of the MD900 helicopters experienced failure of the control cable. The control cable had 186 hours time-in-service (TIS). On July 21, 2008, another MD900 helicopter experienced failure of the control cable. The helicopter had 55 hours TIS. We were investigating the cause of the control cable failures when we received notice of a third failure. Failure of the control cable could result in loss of yaw control and subsequent loss of control of the helicopter. |
| 2008-08-11 | This amendment adopts a new airworthiness directive (AD) for MD Helicopters, Inc. (MDHI) Model MD900 series helicopters that requires modifying the pilot and co-pilot dual-control directional pedal assemblies, or the pilot single-control directional pedal assembly (directional control pedal assembly). This amendment is prompted by an accident which has been attributed to loss of directional control due to failure of the welds in the directional control pedal assembly. The actions specified by this AD are intended to prevent fatigue cracking in the welds that connect the directional control pedal to the pedal shaft, resulting in loss of directional control and subsequent loss of control of the helicopter. |
| 2006-18-01 | This action requires reducing the life limit of certain NOTAR fan system tension-torsion (TT) straps. This action also requires, at a specified time interval, removing each affected TT strap from the helicopter, doing a visual and x-ray inspection, and replacing any unairworthy part before further flight. (Supersedes FAA AD2004-23-15) |
| 2004-23-15 Corrected | To prevent failure of TT strap in the NOTAR system. (Superseded by FAA AD 2006-18-01) |
| 2004-16-08 | Requires installing a fan input force limiting control rod assembly fail-safe device (fail-safe device). |
| 2003-14-51 | To prevent failure of a bolt, loss of a main rotor blade, and subsequent loss of control of the helicopter, accomplish ... (Supersedes FAA EAD 2003-13-51 ) |
| 2003-13-51 | To prevent failure of a bolt, loss of a main rotor blade, and subsequent loss of control of the helicopter, accomplish .. |
| 2002-23-03 | To prevent damage to the longitudinal drive link (drive link), loss of control of the main rotor system, and subsequent loss of control of the helicopter. |
| 2002-22-51 | To detect cracks and pitting in the mast resulting in failure of the mast, separation of the main rotor, and subsequent loss of control of the helicopter. For Alternate Means of Compliance ( AMOC ), contact MDHI Field Service for tr02-002. |
| 2002-15-07 | Prevent fatigue failure of the bellcrank |
| 2002-10-05 | To prevent failure of the hub assembly and loss of drive to the main rotor
(Supersedes FAA AD 2001-07-09 ) For Alternate Means of Compliance ( 2010 AMOC and 2012 AMOC ), contact MDHI Field Service
(Supersedes FAA AD 2001-07-09 ) |
| 2001-25-51 | Integrated Instrument Display System (IIDS) Inspection and Replacement |
| 2001-07-09 | To prevent failure of the hub assembly and loss of drive to the main rotor (Superseded by FAA AD 2002-10-05 ) |
| 2000-18-08 | Prevent damage to the longitudinal drive link, loss of control of the main rotor system, and subsequent loss of control of the helicopter |
| 2000-10-06 | Prevent failure of the drive shaft due to fatigue |
| 99-26-20 L | Hub Assembly Drive Plate Attach Flange |
| 99-16-13 | Airworthiness Limitations - Retirement life (Supersedes FAA AD 97-13-09 ) (Superseded by FAA AD 2010-06-06) |
| 99-05-08 | Establish life limits to avoid fatigue failure |
| 98-12-30 | Hub assembly |
| 97-20-12 | Main rotor swashplate bearing |
| 97-13-09 | Airworthiness Limitations - Retirement life (Superseded by FAA AD 99-16-13 ) |
| 97-12-02 Dec 97 | Link assembly |
| 97-12-02 Priority Letter |
Link assembly |
369/500/600 Series Helicopters
| AD Number | Subject |
| 2013-03-03 | This AD has owners and operators find the cure date for each NOTAR fan blade tension-torsion strap, make a calendar-time retirement life for some straps, reduce the retirement life of some straps, have each strap identified with the expiration date, and creates a component record card for each strap. Over time, moisture can reduce the strength of a strap. This AD is to prevent strap failures, loss of directional control, and subsequent loss of control of the rotorcraft. |
| 2008-15-03 | This amendment adopts a new airworthiness directive (AD) for MD Helicopters, Inc. (MDHI) Model 369A, OH-6A, 369D, 369E, 369F, 369FF, 369H, 369HE, 369HM, and 369HS helicopters that requires repetitive tap inspections of each tail rotor (T/R) blade abrasion strip. This amendment is prompted by an incident in which an abrasion strip separated from a T/R blade. The actions specified by this AD are intended to prevent disbonding and subsequent separation of an abrasion strip from a T/R blade, which could result in vibration, loss of the T/R, and subsequent loss of control of the helicopter. |
| AD2008-20-05 fr | SUMMARY: This amendment supersedes an existing airworthiness directive (AD) for MD Helicopters, Inc. (MDHI) Model 600N helicopters. The AD currently requires modifying the fuselage aft section within the next 24 months to strengthen the tailboom attachment fittings and upper longerons. This amendment retains the current required modification and adds the following requirements: Repetitively inspecting the tailboom attachment fittings; installing inspection holes and attachment bolt washers; modifying both access covers; and replacing broken attachment bolts. These additional requirements were inadvertently omitted from the current AD. This amendment is prompted by the need to correct our mistake and continue the repetitive inspections of the tailboom attachment fittings until the fuselage aft section is modified. This series of ADs is prompted by an accident due to failure of the tailboom attach points resulting in loss of control of the helicopter. The actions specified by this AD are intended to prevent failure of the tailboom attachment fittings, separation of the tailboom from the helicopter, and subsequent loss of control of the helicopter. (Supersedes FAA AD 2006-05-17fr) |
| 2007-12-23 fr | Requires inspecting each landing gear fairing support assembly (support assembly), replacing or reworking certain forward and aft landing gear assemblies, and creating an access hole to facilitate inspections and a recurring inspection. (Effective July 19, 2007) |
| AD2007-09-51 fr | This AD requires, before further flight, removing each affected tail rotor blade assembly and inspecting the bore of the tail rotor blade root fitting. The AD also requires identifying each airworthy tail rotor blade assembly with the applicable helicopter model. The actions specified by this AD are intended to prevent the failure of a tail rotor blade and subsequent loss of control of the helicopter. |
| AD2007-05-51 fr | Requires visual and eddy current inspection of the 600N7636-1, -3, -9, -11, Lateral Mixer Output Link Assembly to determine if cracks exist around link ends. |
| AD2006-08-12 | To prevent failure of the tailboom attachment fittings... For Alternate Means of Compliance (AMOC) for AD using TB600N-007R2, see AMOC linked here or contact MDHI Field Service for hard copy. |
| 2005-21-02 | Detect fatigue cracking of the blade to prevent blade failure... (Supersedes FAA AD 2003-24-01) |
| 2004-22-12 (Alternative Method of Compliance - AMOC) |
Requires replacing the fuselage Station 75 control support bracket assembly (control support bracket), reducing the life limit, and revising the Limitations section of the applicable maintenance manual. |
| 2004-20-08 | Detect a corrosion-pitted or cracked forward or center cable assembly connector and to prevent failure of the cable assembly .... |
| 2003-24-01 | See Helicopter
Technology Company (HTC) Ref. HTC Publications, Service Bulletin 2100-3R2 (Superseded by FAA AD 2005-21-02) |
| 2003-16-11 |
Requires reducing the life limit of the main rotor drive shaft (drive shaft) and changing the life limit on the component history card or equivalent record. |
| 2003-08-51 frc | To prevent a pitch horn from separating from the
tail rotor blade leading to an unbalanced condition,
vibration, loss of tail rotor pitch control, and loss of
directional control of the helicopter... T/R Blade Return Handling Instructions |
| 2002-13-05 |
To prevent loss of the tail rotor
gearbox due to attaching bolts of inadequate
grip length and subsequent loss of
helicopter control. Ref: Aerometals STC SH5055NM or SH4801NM and Aerometals Service Bulletin SB-001, dated 3 Aug 2000. POC: Rex Kampher 916-939-6888. See http://www.aerometals.aero/ |
| 2001-24-51 | Inspect and Repair Tailboom Attachment |
| 2000-25-52 | See Helicopter
Technology Company (HTC) Ref. HTC Publications, Service Bulletin 2100-2R2 |
| 2000-08-22 | Erroneous TOT indication |
| 2000-04-21 | Fuel starvation of the engine |
| 99-25-08 | Thruster Control Cable Conduit Cap |
| 99-20-12 | Bracket P/N 369F51190-1 |
| 99-17-18 | Flight Control Components |
| 99-13-09 | Inspect Fork Assembly |
| 99-08-07 | Relay receptacle contact socket |
| 99-04-12 | Input shaft coupling assemblies |
| 98-21-12 | Inspect overrunning clutch retainer |
| 98-17-14 L | Engine control and warning system |
| 98-15-26 | Inspect main rotor blade for cracking |
| 98-09-02 | Overrunning clutch assembly outer race |
| 98-07-19 | Tail rotor control rod assembly |
| 97-15-08 | Transmission output drive gear |
| 96-10-09 | Inspect blade root end for cracks |
| 96-08-03 | See Flight Trails Heli., Appliances |
| 95-03-13 | Main rotor blade attach lugs (Ref AMOC 120L-12-88) |
| 95-03-11 | Inspect tail rotor blade |
| 94-24-04 | Pitch control assembly |
| 94-18-08 | Tail rotor blade inspection |
| 93-18-05 | Fuel vent line |
| 93-07-10 | Airspeed limitations |
| 91-08-02 | Tail rotor blades |
| 90-24-07 | Main rotor trans. bolts |
| 90-19-02 | Clutch assembly |
| 90-12-03 | Tail rotor bearing assembly |
| 90-01-08 | Driveshaft coupling |
| 89-23-14 | Main rotor collective tubes |
| 89-20-02 | Tail rotor hubs |
| 89-11-05 | Tail rotor strap pack assemblies |
| 89-02-01 R1 | Main rotor blade strap assemblies |
| 88-17-09 R1 | Tail rotor transmission |
| 87-18-12 R1 | Main rotor transmission |
| 87-18-11 | Main rotor transmission and drive shaft |
| 86-20-07 | Tail rotor drive shaft |
| 86-01-04 | Tail rotor blades |
| 84-12-01 R1 | Approved rotor blades |
| 84-11-01 | Control rod |
| 84-01-02 R1 | Rotor system control |
| 82-17-01 | Output gearshaft assembly |
| 82-14-01 | With Chadwick C-20 aux. fuel system |
| 82-01-08 | Lever control rod |
| 81-26-01 R1 | Main rotor drive shaft |
| 80-25-01 | Tail rotor drive shaft |
| 80-24-04 | Placard -front seat occupancy |
| 80-08-04 | (See Chadwick, Equipment |
| 79-10-09 | Tail rotor pitch control assy |
| 78-26-04 | Tail rotor hub assembly |
| 78-20-03 | Fire suppression system |
| 77-21-04 | Clutch and shaft assembly |
| 77-19-03 | Main rotor retention straps |
| 77-09-01 | Emergency float assemblies |
| 77-05-03 | Tail rotor control system |
| 76-19-03 | Damper plunger |
| 75-22-04 | Tail rotor blades |
| 75-22-03 | Tail rotor drive shaft |
| 75-10-04 | Tail rotor blades |
| 75-09-17 | Protection of passengers |
| 75-06-02 | Cargo carriers |
| 74-20-04 | Main rotor blade |
| 74-07-02 | Aluminum tail rotor blades |
| 72-18-04 | VNE limitations |
| 72-16-09 | Tail rotor input gear shaft assy |
| 70-16-07 | Main rotor blade |
| 69-21-01 | Failure of input pinion shaft |
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