Close formation flying with two aircraft by René Birot Articles

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Preface :

Close formation flight with two aircraft is an intense pleasure requiring training and education with skilled instructors, often pilots which have serviced in the army.

This small document is not an exhaustive education for formation flight, instead it is some practical information to know before getting on. It are precise notes taken from theoretical education preceeding practice on two DR400 at the aeroclub of Annemasse on a sunny afternoon 1998.

Fly! allows flight with several users in network, so this document is usable for practicing close formation flight.

Remark: all the images in this document are extracted from... Flight Simulator 98, the Fouga Magister is realised by Johann Ludwig, the panel by the author of this article. The gear is left down on purpose, to allow the usage of the same references than those we can get with fixed gear aircraft.
The Fouga has been choosen on purpose, although not (yet) existing for Fly!, because of his long history regarding training pilots for this kind of exercise.

See here the final result !

 

 

To arrive at this flight situation, you need to train by remembering the next instructions.

Some basic rules before starting :

- the leader need to perform all the manoevers by keeping in mind his wingman which implies :

• don't play with the throttle to keep a speed. Both aircraft flying through the same airvolume are undergoing the same constraints, it's important to keep a same number of rpm.
• don't show-up extreme rpm in order to allow your wingman to keep a margin for acceleration or deceleration to retain the position.
• to perform all evolutions in a progressive way which implies anticipation of manoevers.
• to maintain altitude during the turns.

    2. take-off

• - the leader lines up down the wind to avoid wake turbulences towards his wingman.

  

   

3- The wingman :

• Need to be in the sun if possible
• The position named "refused echelon" is the most indicating for this kind of practice. It is the description of this position which will de detailed hereafter.
• assures the security by having constantly an eye on the leader and by remaining in a position allowing evacuation if required.
• the best distance from the leader is the one which feel confident !

• The flight in line

Keeping position is obtained by the wingman by respecting the following three rules together :

1. The step representing the altitude difference compared to the leader: it must be negative (the wingman is under the leader)

 

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2. The lag representing the horizontal distance (in the direction of flight) separating wingman from leader

   3. The displacement which is the distance separation the two aircraft (2m minimum between the two wingtips)

• For a fair safety, it's essential "keeping the distances" by applying the following values.

   

 

4- Action order:

The wingman's keeping position must always be done in the following sequence:

1. first adjust the negative step, for example by maintaining the leaders wing at eyesight (it's a minimum). This adjustment, although assuring the best visibility, also permits to pass under the leader in case of an unwanted closure.
   
2. then adjust the lag by taking a reference mark to align part of the leader's fuselage with a point on the cockpit.
   
3. finally adjust the displacement by taking a second reference mark, for example on fixed gear aircraft, to align the front wheel and the main gear wheel at his side.

                                                   
                                                                                   

If the front wheel "advances" (movement towards the left in the example mentioned above), we apply a little more throttle, if it "moves after" (movement to the right), we slightly reduce the throttle.

• The wingside changement

Passing from one wing towards another requires the wingman to take a certain number of precautions representing the following actions in sequence :

1. Increase the lag (retard slightly). This is achieved by reducing the power by 100 rpm.
2. Increase the displacement <0 by a wingspan (take position about 10m under the leader).
3. When estimating enough distance, we stop the movement by increasing 200 rpm.
4. Turn 10° to enlarge the path in order to avoid touching the leader. This is the beginning of changeover.
5. Once on the opposite side, keep a larger than definitive distance before flying parallel to the leader.
6. The indicated overspeed (+ 200 rpm) allows to regain the step as a priority.
7. The same overspeed allows then to recover the required lag (reference mark alignment covered here before).
8. Apply the proper speed (reduce the additional 200 rpm) and regain the required displacement by slight throttle adjustments.

• The turn

On light single engine aircraft, it is preferred to make turns with poor bank (15°).

Additionally, on the same aircraft type, as soon as the leader initiates the turn, the wingman, if he's on the exterior side, immediately has to apply full throttle to initiate the climb. Reduce slightly if the reference markers move.

The leader performs the turn keeping the altitude.

The wingman changes his altitude to keep the same step.

If the wingman is at the internal side of the turn, he reduces progressively in order to descent and to maintain at the same level as in horizontal flight.

 

You always have to keep the reference markers aligned (here under the wheels during a left turn and the wingman at the rightside of the leader)

• The regrouping

Watch out to have always sufficient displacement to allow overtaking the leader if needed.

1. the step adjusted and stabilized in height
2. adjust the lag with the throttle
3. adjust the displacement with the rudder or ailerons
   • heading 10° closure, wings horizontal
   • when the position is reached, resume the good heading, the wings still horizontal

The regrouping is often operated as follows:

• the aircraft takes off at 5 second interval and keep the same heading
• they both turn at 90° to behave parallel
• the wingman makes a regroupment manoever by flying at higher speed than the leader and by flying a 10° closure heading
• the wingman finishes by a type manoever indicated below

 

• Conclusion

The close formation is a passioning exercise but it remains dangerous, our light aircraft having slow speeds don't permit vast possibilities to react.

Those single lines of explanation only offer a brief overview of the work to perform before achievement.

Although, with willingness and attention, it's fairly feasable, only after a training with handy instructors.

Finally, unless several rules and technics indicated in the preceeding pages, the respect of the following safety requirements is mandatory :

• NEVER A POSITIVE STEP
• NO UNCONTROLLED MANOEVER
• TAKE A BREAK AFTER EACH KEY PHASE WHILE RESPECTING THE SEQUENCE:

  1- STEP

  2- LAG

  3- DISPLACEMENT