Non Standard Flights are those which, for the operating flight crew and/or their Company, are outside their normal operating experience.
Overall statistics for Accidents and Serious Incidents show that non revenue flights have a much higher risk of producing an accident or serious incident than the revenue flying which most professional flight crew routinely undertake. A similar, though statistically unproven conclusion may be drawn in respect of revenue flights which are planned to depart from, and return to, the same aerodrome when operated by an airline which predominantly carries out flights from one location to another. A further, also statistically unproven but highly likely, claim is often advanced that airworthiness function flights carried out by flight crew who are not trained and experienced as professional test pilots are also more likely to result in an accident or serious incident. A causal factor can be that the procedures documented within the Operations Manual and procedures implemented by an Aircraft Operator for such flights are inadequate.
Two issues that have usually been associated with this increased risk, either singly or together, both relate to the substantially different nature of such flights from a flight crew perspective compared to the routine of normal operations:
- An unfamiliar environment with a significantly modified context for standard operating procedures, in particular the possibility in many cases of an absence of the usual en route period of relative inactivity.
- The apparent willingness of a minority of flight crew making non-standard flights to apply less than their usual rigour to the use of prevailing standard operating procedures.
Common Types of Non Standard Flight
Whilst any definition of what is non-standard must be made by reference to what is standard for any particular operator, a number of generalised cases can be identified:
- Any flight that deviates from laid down Rules and Regulations.
- Positioning or ferry flights (both fully and conditionally released to service)
- Pleasure, sightseeing or other ‘air experience’ flights
- Display or ‘exhibition’ flying for the benefit of persons on the ground
- Airworthiness function or check flights after maintenance input or in association with aircraft acceptance or hand back
- Flights to develop operator-specific visual approach/departure procedures
- Flights undertaken specifically and solely for crew training or familiarisation purposes
- An exceptional freight-only flight made by an operator which does not normally undertake such flights
- Airworthiness certification flights (unless flown by trained test pilots following their main occupation)
- Formation flying where it is not part of Standard Operating Procedures.
Opportunities to Mitigate the Risk
There are several ways in which the particular risk associated with non standard flights can be restored to the level which applies to whatever a ‘standard’ flight for an operator and/or the crew involved is. Not all will necessarily apply to an individual case but many probably will.
- The Company Operations Manual should include a definition of non standard flights appropriate to the normal business of the Operator. This should state that all standard operating procedures will apply unless specifically suspended, or supplemented, by a specific instruction.
- A Flight Operations Risk Assessment specific to the generic task should have been carried out and remain valid prior to any non standard flight being operated. Everyone involved in the preparation and operation of any flight covered by the generic risk assessment must then work to its detailed assumptions and requirements. All points of significant detail should be cross checked by a qualified person as defined in the Risk Assessment.
- For each type of non standard flight (except positioning flights with no non-standard tasks requested and flights without degraded or inoperative systems that would require specific procedures in addition to or instead of normal SOPs):
- the Operations Manual should contain a generic but comprehensive supplementary brief which covers the operation of each type of non standard flight.
- if the check schedule requires operation of intentionally degraded aircraft systems then a task-specific programme of initial and recurrent training should be mandated for the operating crew.
- flight crew allocated to operate the flight should be required to fly a similar detail in a simulator not later than their most recent simulator proficiency check unless a similar non-standard flight profile has been flown since that time.
- appropriate additional time should be rostered for pre-flight briefing for all those persons who will occupy flight deck seats.
- the role of any persons to be carried in the aircraft cabin but who will have access to the flight deck during the flight should be defined in writing and form part of the overall procedures for the conduct of the particular type of flight.
- supplementary or amended checklists should be provided if the sequence of flight crew actions will not follow that covered by sole use of the normal and/or non-normal checklists; the use of these checklists should form part of the simulator training detail.
Increased Risks & Examples
Loss of Control
- CRJ2, en-route, Jefferson City USA, 2004: On October 14, 2004, a Bombardier CL-600 belonging to Pinnacle Airlines and on a positioning flight crashed into a residential area in the vicinity of Jefferson City Memorial Airport, Missouri.
- B737, manoeuvring, west of Norwich UK 2009: On 12 January 2009, a B737 operated by easyJet, overhead Norwich UK, experienced a loss of control during functional checks of the flying controls. A successful recovery was achieved following significant loss of height.
- A320, vicinity Perpignan France, 2008: On 27 November 2008, an A320 operated by XL Airways Germany, crashed into the sea at Canet Plage, France, following loss of control, without recovery, during a low speed handling test attempted at low altitude as part of a function flight.
- DC86, en-route, Narrows VA USA, 1996: On 22 December 1996, a Douglas DC-8-63 operated by Airborne Express, crashed in mountainous terrain near Narrows, Virginia, USA, following loss of control attributed to mishandling during a post maintenance function flght.
Controlled Flight Into Terrain (CFIT)
- Air New Zealand DC10 crash Mount Erebus 1979
Loss of Separation
- SH36 / SH36, manoeuvring, Watertown WI USA, 2006: On 5 February 2006, two Shorts SD-360-300 aircraft collided in mid air while in formation near Watertown, WI, USA; both aircraft suffered damage. One aircraft experienced loss of control and impacted terrain while the other made an emergency landing, overunning the runway, at a nearby airport.