Knauff & Grove Soaring Supplies

3523 South Eagle Valley Road

Julian, Pa 16844

 

Phone (814) 355 2483 Fax (814) 355 2633 Email: knauff@eglider.org

www.eglider.org

 

Keystone Gliderport                           Schempp-Hirth Sailplanes                Soaring Books and Supplies

 

 

March 22, 2001

Aero Tow Emergencies

 

 

How many aero tow emergencies can you think of?

 

Federal Aviation Regulations require each pilot to be trained in towing emergencies. Approximately 15% of all glider fatalities occur during the first few seconds of flight.

 

A group of eight experienced glider pilots were asked this question. Most pilots thought of ten possible emergencies. One thought of sixteen. The list below is the result of the emergencies listed by this group, plus several more added by Tom Knauff & Doris Grove.

 

Aero Tow Emergencies

 

1.      Rope Break........................................................... 8

2.      Canopy not latched................................................ 3

3.      A control not connected......................................... 6

4.      Wing drop (ground loop)....................................... 6

5.      Air brakes opening................................................ 6

6.      Flaps in wrong position.......................................... 1

7.      Towplane power failure......................................... 8

8.      Tow speed to slow or fast...................................... 3

9.      Being towed too far downwind.............................. 1

10.  Controls hooked up backwards............................. 1

11.  Tire blow out......................................................... 1

12.  Tow rope will not release....................................... 5

13.  Glider becomes too high........................................ 5

14.  Someone moves onto runway................................ 2

15.  Tow rope catches on something at start of launch... 1

16.  Slack rope / rope wrapping around glider............... 1

17.  Improperly installed component.............................. 1

18.  PIO....................................................................... 1

19.  Frozen controls...................................................... 1

20.  Turbulence............................................................ 1

21.  IMC...................................................................... 1

22.  Inability to recover from low tow position............... 2

23.  Knot in rope                    ...................................... 1

24.  Overrun tow rope.................................................. 1

25.  Traffic conflict / mid-air collision............................. 3

26.  Wing runner error.................................................. 1

27.  Airspeed indicator not working.............................. 1

28.  Altimeter not adjusted properly.............................. 1

29.  Tail chute opens..................................................... 1

30.  Water ballast disconnects and spills into cockpit..... 1

 

31.  Snake / Bee / Wasp in cockpit

32.  Unbalanced ballast in wings

33.  Seat belts undone

34.  Pitot / Static ports clogged

35.  Smoke in cockpit

36.  Panicky passenger

37.  Pillows / seat ballast moves

38.  Controls restricted (control locks, rudder pedals too far forward)

39.  Tail dolly on

40.  Canopy fogs up

 

There surely are more.

 

Note how many can be directly attributed to an improper assembly, preflight, or improper pre-takeoff checklist inspection. Many pilots do not carefully perform a pre-takeoff checklist, believing an emergency is unlikely to occur to them.

 

Consider how many can be affected, even prevented, by a trained, alert bystander such as a crewmember, tow pilot or wing runner.

 

Accidents can and do happen when a pilot is unprepared for an in-flight emergency. In most cases, the glider flies just fine even with an open canopy, a snake in the cockpit, etc. The primary task for the pilot is to recognize a situation as early as possible and fly the glider in a controlled fashion.

 

The pilot recognizes some anomaly listed above. The temptation may be to continue the flight for fear of embarrassment, a macho reaction that the pilot can handle the emergency and continue, resignation there is nothing the pilot can do at the moment, or impulsive behavior reacting too quickly without thinking things out.

 

Pilots must have a prepared plan of action to the listed emergencies. In most cases, there are three plans of action depending on the phase of flight.

 

Plans of action

 

Phase 1. There remains lots of runway ahead.

 

The plan of action when a problem is perceived very early in the launch is to simply release and land straight ahead. Care must be taken to stop the glider in a controlled fashion. There is a very strong tendency to continue the launch rather than releasing, and investigating the problem. If there seems to be something wrong at the beginning of the tow, do not hesitate – release immediately!

 

Phase 2. The glider is too high to land on the remaining runway.

 

This emergency plan of action will be to land in a suitable area planned in advance in anticipation of a possible problem. This might include an intersecting runway, farmers field or even a planned, controlled crash into a tree row, lake or whatever. Regardless, done properly, injuries should be minimal if any.

 

3. The glider is high enough to return to the runway.

 

Performing a 180 degree turn back to the runway should be practiced at least every year. The minimum altitude should be planned before launch and this minimum altitude noted aloud as the glider passes through the critical altitude.

 

The left hand.

 

Glider pilots fly with their right hand. The left hand is ready for four possibilities:

 

1. Ready to pull the release knob. General practice is to have the left hand near, but not on the release knob during the first phases of flight in case of an emergency.
2. Ready to close the dive brakes in case they are not locked before the launch commences, or open because of a rough runway surface.
3. Ready to grab the canopy in case it opens in flight. There is often a very slight warning before the canopy suddenly opens. An alert pilot might grab the canopy or press on the appropriate rudder to slip the glider through the air keeping the canopy closed. If it does open, no attempt should be made to close it until after reaching a normal tow height.
4. Moving the flap handle in case the flaps are in, or move to an incorrect setting.

 

The moment you signal the tow pilot to begin the tow, your total concentration should be on the possibility of an emergency, and effecting the appropriate plan of action for each phase of flight.

 

Assembling your glider

 

Many glider accidents occur as the result of an improper assembly of the glider. After you assemble your glider, it is very important to have another person inspect the glider for proper assembly. Even if they are not familiar with your glider, you can show them what you did during the assembly to assure it is done properly. The tow pilot in particular will be interested in knowing you did have this assembly check, so it has become common practice to place a mark on the wing root tape of the left wing so the tow pilot can see it before beginning the launch.

 

Expect the wing runner to ask if you did a positive control check before you are offered a launch.

 

Many emergencies are covered in detail in the books, After Solo, Transition To Gliders, Accident Prevention Manual for Glider Pilots, by Thomas Knauff, and Gliding and Gliding Safety by Derek Piggott