Handwritten notes criticising a SNECMA report on a steering incident

In this document

These two pages are handwritten critical notes, written in response to a report (likely the SNECMA report on the DS 19 steering incident) which they quote in inverted commas to correct point by point.

On the description of the incident

The note takes up the report's sentence: “The car veers to the left, difficulties in straightening the vehicle which leaves the road and hits a tree” p. 22. The author draws a logical remark from this: this wording “implies that it veered without being prompted by the driver” and that this occurred “on a straight line”; he insists on the fact that the car “did not therefore lock in a position but went to the left” p. 22.

Faced with the report's sentence on an “attitude instability that no adjustment could ever entirely eliminate”, the author asks a technical question: “Have the pivot ball joints been examined, is there not one seized?” p. 22.

Technical correction on the hydraulic spool valve

On page 23, referenced “Page 2. – § 1.”, the author corrects a wording in the report: one must read “the other spool valve returned by its spring” and not “the other piston”. He then specifies that the spring is not the only factor involved: “it is pushed by the fluid, the pressure of which increases if there is any resistance” p. 23.

Marginal annotations refer to “p.2 / III” p. 22 and a handwritten initial appears at the top of page 23.

Context

The vocabulary used — spool valve, return spring, hydraulic pressure — corresponds to the operation of the power steering and hydropneumatic systems developed by Citroën, of which Paul Magès was the lead engineer. SNECMA, an aeronautical engine manufacturer, was a professional client using DS 19s; a steering incident on one of their vehicles gave rise to an internal investigation, several documents of which are kept in this same collection.

Archivist's perspective

The tone is that of a technical expert reviewing, almost line by line, a report written by a third party — probably to point out its linguistic approximations and investigative gaps. It seems to be a draft of a response or internal commentary, rather than a document intended to be transmitted as is.

The precision provided on the operation of the hydraulic spool valve — returned both by a spring and by the fluid pressure — betrays a fine knowledge of the mechanism, consistent with Magès' expertise on hydropneumatic circuits. The explicit reference “Page 2. § 1.” suggests that this document annotates a specific identified report very precisely, probably SNECMA Note no. 63/667 or the correspondence accompanying it, such as the letter from P. Mahoudeau to M. Clément.

In the absence of an explicit date in the document, the dating remains unspecified, although the content likely places it in the same episode as the documents dated June-July 1963.