Emergency Airworthiness Directive

RSA AD No 07-001

Applicable to: All Boeing 75, A75, B75, D75, E75, and IB75 series aircraft.

Owners and operators of the abovementioned aircraft types issued with a certificate of airworthiness in terms of Part 21 or operating on an authority to fly issued under Part 24 of the South African Civil Aviation Regulations 1997, as amended are hereby advised that the grounding order issued, which prohibits the operation of these aircraft in the RSA until an acceptable level of safety can be demonstrated, shall remain in force subject to the following.

Aircraft fitted with a Pratt & Whitney 985 series engine which allows for a take off power setting of 450 horse power to be utilised, no inspection criteria has been determined at this time and the grounding order remains in effect.

The owners of Aircraft fitted with Continental, Lycoming or Jacobs engines are required to perform the following prior to further flight.

Remove the engine from the airframe and remove the four engine mount support studs. Depending on the installation bolts have been utilised in some cases. The inspection criteria for the studs will therefore apply.

Carry out the following inspections

1. Check all four engine mount clusters using an x-ray method of inspection.
2. Inspect engine diaphragm plate in the vicinity of the mount studs for signs of fretting possibly indicating loss of or incorrect torque of the castellated mounting support nuts.
3. Replace all studs or bolts as the case may be with new items. Maintenance personnel must pay due regard to the stud size required. This will be determined by the thread size in the airframe support boss and not the stud shank diameter which will normally remain at 7/16"
4. Inspect airframe stud support boss threads for damage. Should damaged or pulled threads be found effect repairs in accordance with the maintenance manual which allows for the replacement of step studs. Should repairs already have been performed on the threaded boss and the hole diameter exceeds 9/16 of an inch and thread damage is noted a threaded bush will have to be manufactured and installed into the airframe support boss in accordance with the requirements as laid down in the maintenance manual. In this case standard studs can be refitted after rework has been carried out
5. Should the installation differ from abovementioned an alternate means of compliance must be requested.
6. Inspect all engine to mounting frame sandwich support rubbers for condition as well as the support bolts in this area and replace as necessary.

The engine may be reinstalled after necessary repairs and replacements have been effected. Note a dual inspection of engine controls is mandatory. As well as the required certification in the applicable logbook of the maintenance performed during this inspection.

All positive and negative findings must be reported in writing to the CAA airworthiness section. Once all required maintenance has been performed and the aircraft certified safe for flight, a request for the up-liftment of the grounding order imposed on the aircraft in question can be requested. Submission of the maintenance performed together with the necessary certification is required to be submitted with the aforementioned request.

Should an owner of one of the abovementioned type aircraft wish to submit an alternate method of compliance for consideration, which will achieve an acceptable level of safety, he/she may do so

Compliance: Prior to further flight

Effective date: 30’th July 2007.

Reference: J15/12/302