Aircrew Flight Equipment:
N-Type Oxygen Mask
The N-Type oxygen mask is one of the winged unicorns of historic aircrew equipment, not much is known about this mask, and very little documented evidence found. This article is written in order to document my research into this little mystery.
"N-Type" and "Type N" syntax are used interchangeably on all British mask types.
AP Evidence
So far, I have found one single official reference to the N-Type in an Air Publications (AP). Quote from the September 1969 release of AP-3456E (The Aircrew, Airmanship and Aircraft Performance), Part 1, Section 2, Chapter 1 (Oxygen Equipment and Assemblies), Paragraph 27 regarding the adaptation of the economiser system for pressure breathing:
The mask used with this assembly was the Type M Mk2 oxygen mask. A Type N was also introduced for smaller faces.
Reputable Books
It is mentioned in the book Into Thin Air (by the IAM), where the below summary came from:
It was the first British pressure-demand breathing mask, developed in the 1950's to replace the unpopular American A-13 pressure-demand mask, which had been in use in the RAF for a short time.
It was developed alongside the M-Type mask, which was it's non-demand sister. The main reason for the development of these two masks was the invention of the inturned lip, improving sealing to the face.
After a short service, it was replaced by the P-Type mask for pressure demand breathing when the Gabb harness was invented in the late 1950's. The P and Q series masks are still current issue in the RAF, half a century later.
Possible images
The following images from airsceneuk.org.uk show what may be an N-Type, purely based on a process of deduction. The images are of a young Roly Beamont in the P1A Lightning prototype at Boscombe Down.
For the following reasons this mask aligns with the description in Into Thin Air, but not AP-3456E.
- The mask in these images is a "pressure demand" mask, as it's missing the aluminium knob of the expiratory valve associated with the J-Type and M-Type "pressure breathing" masks.
- It definately precedes the P/Q series of masks as it uses a conventional webbing harness, not the later Gabb harness.
Other notes on the mask photographed:
- Even though the facepiece shares features / shapes of the M-Type and M-Type Mk1, the hose is on the left (all three M-Types' hoses were on the right); the P/Q series continued with hoses on the left.
- The image is not mirrored / flipped, as the airframe text is readable, and the microphone cables re always on the left, and hence the mask permanent fitted side too.
Other general observations: In the images, Roly wears a customised Mk1 protective helmet, with an unofficial visor modification, where it appears a Mk1 visor has been removed from it's harness and screwed directly to the helmet shell. He also wears an F-Type flying inner cloth communications helmet under the Mk1.
Deduction
Into Thin Air and AP-3456E disagree on a fundamental characteristic:
- AP-3456E states the N-Type was introduced as a smaller sized alternative mask to the M-Type MK2. The M-Type masks were "Pressure Breathing" type masks, so logically so the N-Type should also be - so you could use it in the same aircraft types as the M-Type mask.
- Into Thin Air clearly describes the N-Type mask as a "Pressure Demand" mask, which is a very differnt technology to "Pressure Breathing", and can't to be used in the same aircraft as the M-Type masks.
Is AP-3456E wrong?
The end result is that I'm confused, as the only evidence I've found so far is conflicting! Hopefully something else will come to light at some point!
Help with this article
If anyone reading this has any more images / information (such as an AP) of the N-Type mask, or even a physical mask itself, please get in touch!