British Gliding Association Aircraft Inspection
Recommended

Number:
021/10/2001
Date: 1st October 2001

Issue:
1

Subject:

Canopy Jettison and Top mounted instruments

Applicability:

All gliders with central instrument pods or instruments mounted on top of panel fairing.

Accomplishment: Whenever modifications are carried out to top mounted instruments (including GPS antennas)

Reason:

Possibility of canopy jam during jettison in unusual flying attitudes. Some attitudes may cause an aerodynamic suction to build up under the canopy and the aft face of the forward frame of the canopy to become jammed against the forward edge of top mounted instruments (typically compasses). A pressure differential of less than 1 psi. would need several hundred pounds of force to lift the canopy over any object.

Instructions:

1. Ensure that any top mounted instruments are mounted in a position approved by the Glider manufacturer 2. Do not introduce any un-approved additional reinforcement to the instrument mountings or fairing 3. Assess the possibility of interference with canopy jettison and emergency egress from the aircraft 4. On approved types the fitting of ‘Rotger’ hooks should be considered 5. Ensure any manufacturers inspections or modifications regarding canopy jettison are reviewed

Approved By Jim Hammerton, Chief Technical Officer

Issued by - The British Gliding Association Ltd, Kimberley House, Vaughan Way, Leicester, LE1 4SE, U.K. Note: Mandatory inspections must be recorded in the aircraft log book, unless specified, and certified by an appropriately rated BGA inspector.
Optional inspections should be entered into the D.I. book or log book as appropriate. Optional inspections may be certified by a BGA Pilot. Alternative methods of compliance will be considered providing an equal level of safety is accomplished. Contact BGA for authorisation.