Jet Blast

[bglass]

Greetings all,
We have a problem developing at my local airport where the lack of real estate is forcing GA and airlines together into what I call a dangerous situation.
The problem is the airport company is creating a new jet tarmac close to the runway that GA uses.
The jets taxi in and push back out with their tails at 90 degrees to the GA runway.
The jets taxi in and then turn to their gate exposing the GA runway to their jet blast.
The distance is 93 meters at the turn point to the center line of the GA runway.
The jets are A320 and B737- 800.
I am now of the opinion that GA operation, at the same time as the jets are arriving or departing, is at risk of being blown off the runway.
Has anyone come across this else where? I seek opinions as to the safety of this situation.:confused:

[mustafagander]

Try IFALPA SARPS, there ought to be guidance therein.

[Fieldmouse]

A quick look at MOS 139 here in Oz shows that the operator has a duty of care under 6.6.1 and I would assume the same applies in NZ.

"6.6.1 General
6.6.1.1 The aerodrome operator must protect people and property from the
dangerous effects of jet blast. Information on specific jet engine blast
velocities, including lateral and vertical contours, for a given aircraft model is
given in the Aircraft Characteristics - Airport Planning document, prepared for
most aircraft models by the aircraft manufacturer."

But I can't find any specific regulations other than the standard separation distances shown in 6.3-5.The reg is more about the protection of people and buildings from jet blast rather than the effects on nearby runways. Be worth raising the issue in writing to the airport authority. Good Luck!

[Fieldmouse]

Yep there it is in the NZ Regs,

139.69 Public protection
(a)
Each applicant for the grant of an aerodrome operating certificate shall provide at their aerodrome—
(1)
safeguards to prevent inadvertent entry of animals to the movement area, and safeguards to deter the entry of unauthorised persons or vehicles to the aerodrome operational area; and
(2)
reasonable protection of persons and property from aircraft blast.

Good old duty of care. Now pull down the blast diagrams for A320 and B738 and see how 93 metres measures up.

[OverRun]

There is a genuine problem here.

Boeing 737-800 Blast Clearance (http://profemery.info/aviation/738_blast.htm)

[Fieldmouse]

Would there be a chart for idle and breakaway thrust. This seems to be a taxiing from the ramp problem rather than a takeoff thrust issue.?

[OverRun]

Sorry about that - wrong chart. See the breakaway thrust chart here:

http://profemery.info/jetblast.gif

Note that this chart shows distance from the tail of the plane; not sure if your 93m is measured from the wheels or the tail.

[bglass]

Thanks, I have been unable to find anything specific to our situation but I believe what you say is correct.
I have years as an engineer on these jets and know the sort of havoc they can play with a light aircraft. As a PIC of a commercial aircraft, the situation makes me very nervous, to the point of not operating on or off that runway when there is any risk of the jet blast.:sad: