August , 1934 AIRCRAF T ENGINEERING Instruction s to Aeroplane Owners and Ground Engineer s on Essential Modifications No . 14 of the year 1934 Applicants whose applications are no t accepted, No . 19 of the year 1934 owing to these provisions will be given the Owing to rapid wear of th e old patter n valve- Cases have occurred on D.H.60 G., "Moth," opportunity of early examination in London, rocker adjusting screw, Part No. 822, on "Mot h Major" and D.H.82 A "Tiger Moth" or, alternatively, of being placed on a waiting Pobjoy "R " type engines, ther e is a danger of aeroplanes with Gipsy III and Gipsy Major list for the next board to be held in the place th e valve clearance increasing sufficiently during engines of fatigue cracks developing in the in question. flight to allow the rocker to foul the valve- exhaust extension pipe (part No. 39978 Mk.l Cancellation. Notice to Aircraft Owners and spring cap. New type screws, Par t No. 822/1, and Mk.2) at the point where the pipe is sup Ground Engineers No. 6 of the year 1934 is which are harder and have the striking pad ported by a clip, owing to the length of the hereby cancelled. thickened up, must, therefore, be fitted not overhung portion. These pipes can be readily May 8, 1934. later than the next top overhaul. identified by the length of the overhang, Th e minimum allowable clearance between which is 24 in., and by perforations in the rocker and spring cap with valve closed and No . 16 of the year 1934 form of round holes at the aft extremity. clearance adjusted, is 3½ in., and in no circum There is a risk of fire occurring on aircraft Two other types of exhaust extension pipe stances may the rocker be filed to obtain this. fitted for wireless transmission, because of the arc fitted to certain aeroplanes concerned, but Since th e clearance is affected by th e push-rod possibility of a breakdown of insulation between arc not affected by this Notice. They may be length or by a badly fitting split cotter, it is th e drum of the aerial winch and the aerial identified by the exhaust outlet being in the importan t to ensure tha t the push rods, which winch frame when a trailing aerial is in use. form of two long slots extending the whole are marked with th e number of their respective Ground engineers must ensure tha t the aerial length of the overhung portion in the one cylinders just below the ball end, are in their winch frame is electrically bonded to the main type , and in the other by the pipe being made correct position, and tha t the split cotters are eart h system of the aeroplane in a satisfactory of stainless steel and having an overhang of approximately flush with th e lower edge of the manner. No daily certificates may be signed 17 in. spring cap. in respect of aircraft on which this bonding Pipes answering to the description given in Note.—The inlet and exhaust push-rods ha s not been carried out or is not satisfactory. paragraph 1 above are to be removed immedi for a particular cylinder bear the same May 9, 1934. ately and carefully examined around the number, but the exhaust rod is th e longer of portion underneath the supporting clip for th e two. an y sign of fatigue cracks. If the pipe is No . 17 of the year 1934 Attention is also drawn to the method of found to be in good condition, it may con The attention of all concerned is drawn to assembling the two collars positioning th e inner tinu e in use after being shortened by cutting th e possibility of damage occurring to aircraft valve-spring ; it is imperative tha t the project off the rear end to give an overhang not and/o r tyres fitted thereto as a result of the ing lip of th e collar faces towards the rocker in exceeding 17 in. Should any sign of fatigue tyres not having been maintained at the bot h cases. cracks be discovered the pipe must be rejected. correct pressure. Certificates of airworthiness of any aircraft Pipes rejected under paragraph 3 must be I n many cases the tyres provide a large fitted with engines of the type referred to in replaced by pipes of the same design shortened proportion of the shock-absorbing capacity of this Notice shall be liable to suspension or can as described, or by pipes to one of the designs the under-carriage, and in such cases there is cellation if the requirements herein have not given in paragraph 2. considerable danger of damage to the aircraft been complied with. Certificates of airworthi structure owing to loss of shock-absorbing The Certificates of Airworthiness of aero ness will not be renewed, and ground engineers planes affected will be liable to suspension or capacity of the tyre if in an over-inflated state. must not sign daily certificates in respect of cancellation if this modification has not been On the other hand, insufficient pressure may such aircraft, unless the instructions have been carried out within three months from the date satisfactorily carried out. allow of excessive flexing of the cover and of this Notice. Certificates of Airworthiness consequent breakdown of the walls, or damage May 8, 1934. will not be renewed and Ground Engineers t o the tyre as a result of pinching, or to the must not sign Daily Certificates in respect of wheel as a result of impact with the ground. No . 15 of the year 1934 such aeroplanes after the expiration of this I n order that ground engineers may ensure Examination Boards will sit for the purpose period unless the modification has been carried tha t correct pressures are employed, a schedule of examining applicants for ground engineers' out correctly. is attached as an appendix hereto giving licences a t the following places and times :— approved types of tyres for under-carriage Jun e 22, 1934. (a) London, weekly, on each Tuesday in and tail wheels, and the correct air pressure July , August and September, 1934. for varying all-up weights of aircraft. These No . 21 of the year 1934 (b) Croydon, on th e second Friday in July, pressures should be maintained as accurately August and September, 1934. Considerable risk of fire may arise if W/T as possible ; there should not be a variation (c) Manchester, on the first Friday in transmittin g apparatus is operated in an of more than plus or minus 10 per cent. August, 1934. aircraft unless each of the separate components I t is pointed out that pressure gauges which (d) Bristol, on the first Friday in July, and the complete aircraft have been adequately are fitted to or form part of the tyre pump bonded. cannot give accurate readings of the pressure (e) Glasgow, on th e third Thursday in July, of air in the tyre, since the pump has to over Where W/ T apparatus is installed in aircraft come the resistance of the tyre valve. Pres ground engineers should verify that the aircraft Applications for licences should be made on sures should therefore be checked by the has been correctly bonded and tha t the bonding C.A. Form 2B, which is obtainable on request, application of a gauge to the tyre valve. is maintained. to The Secretary, Air Ministry (C.A.2), Adastral Jun e 1, 1934. When new or replacement components are House, Kingsway, London, W.C.2. Applica [The Schedule—which occupies nine pages in the original Notice fitted to an aircraft in which transmitting W/ T tions for extensions t o existing licences will also —is not reproduced here. Copies of the complete Notice can be apparatu s is installed, ground engineers should be dealt with at these boards, and such appli obtained by those interested on application to the Air Ministry, Kingsway, London, W.C.2.—EDITOR.] ensure that the individual components have cations should be made on C.A. Form 2D to been bonded and that such components are th e above address. When forwarding the No . 18 of the year 1934 bonded to the aircraft. Under para . 4 of Design application, the applicant should indicate the Leaflet E.5 of A.P.1208, all aircraft carrying provincial centre which he wishes to atten d for Wit h reference to paragraph 1 of Notice to W/ T transmitting apparatus are required to be examination, if he is unable to take the ex Aircraft Owners and Ground Engineers No. 15 bonded in accordance with Air Ministry General amination in London. of 1934, the Examination Boards notified Equipmen t Specification No. D.T.D.G.E.125 Application for examination at the centres therein to be held in London, Croydon and (latest issue) Par t II or other approved specifica named at (c), (d) arid (e) above can only be Manchester, during the month of August, 1934, tion. Copies of Air Ministry Specification accepted provided tha t th e application, together have been cancelled. No. D.T.D. G.E.125 may be obtained from His with the appropriate fees, is received twenty The Boards will be resumed in September, Majesty's Stationery Office, price 1s. 0d. net, or eight days before the dates specified, and pro bu t a further Notice will be issued notifying the Is. l½d. post free. vided also tha t the total number of applications exac t dates on which the Boards will be held. received is within the capacity of the board. Jun e 2, 1934. Jul y 14, 1934.
Aircraft Engineering and Aerospace Technology – Emerald Publishing
Published: Aug 1, 1934