H O F T E C


Courses
Winter Seminar

Warning: In case information presented in this seminar differs from that published in your POH, follow the directions of the POH. However, verify that directions given in the POH also apply to aircraft operations at very cold temperatures.

1. Need

2. Equipment - is designed to operate for +15° Celsius only

3. Heat flows

4. Airframe

  1. Snow blowing into openings. Melt-freeze cycles
  2. Snow in controls causes imbalance and may cause control flutter
  3. Cessnas with control locks in place and snow loads on tail get damaged at the instrument panel
  4. Drain holes become blocked with dirt and ice.
  5. Battery – take home if not used regularly. Has only ½ the normal capacity.
  6. Avionics – remove for long periods of inactivity to avoid corrosion
  7. Preheat cabin so that gyros are warm – saves bearings.
  8. Tires and oleos will have lower pressures in them
  9. Remove snow carefully – don't sweep into cracks and controls. Don't assume it will blow off.
  10. Ice in hinges must be melted – not crunched out using control movement
  11. Frost formation externally is deadly
  12. Control cables are slacker in winter – may bang around in structure
  13. Effect on airframe of brakes-on when sliding off ice onto pavement
  14. Avoid drifts on runways
  15. Short days – make sure lights work
5. Engine
  1. Preheat engine for at least 45 minutes, with covers on, when temperatures are 25° F or below.
  2. Plug engine heaters in early. Make sure heater works by feeling cylinder heads.
  3. Private owners – don't leave heater plugged in. Condensation produces rust.
  4. Don't face engine into a cold wind.
  5. On walk-around make sure breather pipe is not obstructed with ice from condensate frozen after last flight.
  6. Oil has a low Specific heat – it doesn't heat engine parts very effectively
  7. Oil heaters cause moisture condensate which in turn helps corrosion.
  8. Co-ordinate early departures with dispatch the day before.
  9. Propeller is a heat sink. Cover blades for maximum warming of crankshaft bearings while pre-heating.
  10. Remove covers as last item in preflight – start engine within 5 minutes of removal
  11. Lycoming - H2AD engines must be preheated thoroughly
  12. Prime engine. Wait a few (5) seconds for fuel to vaporize before cranking engine
  13. The colder the more the primer strokes and the longer you wait before cranking. Use minimum number of strokes.
  14. Priming washes lubricating oil off cylinder walls.
  15. Don't pump throttle on C-152 while cranking – no accelerator pump on some models
  16. Start engine with alternator 'Field' off to conserve battery
  17. If engine misfires on start-up, and then will not start, plugs may become frozen. Put airplane in warm hangar
  18. After a 10 second starter engagement wait equal time for starter to cool before restart
  19. If an engine does not start after 10 seconds of cranking something is likely not right. Seek advice from dispatch/instructor/maintenance
  20. Maintain oil pressure below 100 psi. Continually monitor oil pressure
  21. Do not add power until oil temp gage is off the peg (75 F) Idle at 1000-1100 RPM.
  22. Thick oil sometimes does not flow rapidly enough through hydraulic valve lifters.
  23. Internal cylinder temps below 900°F produce Lead bromide and carbon fouling Under 1500 RPM). Lead forms again above 1300° F (Climb Power). Make sure you check that RPM rise on shut-down is very nearly 20 RPM. If less than 20 or higher than 50 RPM, inform maintenance.
  24. On Controllable props do not let RPM drop by more than 50 during prop cycling. Cycle more often in winter.
  25. Use carb heat during the warm-up period to allow fuel to vaporize properly.
  26. Carb heat is unfiltered air – so be careful you don't run engine over loose material.
  27. Lean mixture at all times except climb-out. Learn mixture control position for ground operation..
  28. Don't do run-up over ice or snow or gravel. Propeller is easily damaged ($3000) .
  29. Make sure winter kit is installed.
  30. Due to higher idle RPM in winter, plan your taxiing so as to avoid taxiing with brakes on.
  31. Avoid taxiing through puddles at near freezing temperatures. Brakes freeze at altitude
  32. Frozen water cannot be drained from the fuel strainers
  33. Frozen water droplets in fuel line may block line enough to cause engine to falter
  34. Avoid power-off descends – use flaps for drag and keep up the power.
  35. Make slow adjustments to the power - 5 second rule from idle to full power or vice versa
  36. Cylinder head temperatures should not change more than 50 degrees/minute. Plan descent far enough out.
  37. STORAGE – Use AeroShell 2F. (Exxon Royco 482 equivalent) Change Oil and Filter. Run engine 15 minutes. Drain when reactivating.

 

Winter Operations Questions

The following questions are based on the information presented during the 'Winter Flying Seminar'. It is imperative that pilots know the answers to these questions. At stake are safety of operations and operating costs. (Test Français)

Pilots must achieve a minimum of 90% correct responses on this quiz in order to be permitted to fly Laurentide aircraft in temperatures below 0°C. In all cases the test must be corrected to 100% with the help from an instructor.

1. How long before start-up should the engine heater have been plugged in?__________________

2. Which aircraft's engine must absolutely not be started if not plugged in prior to start-up? ____________

3. What specifically should be checked on spinners in winter? __________________

4. What are the 3 ways heat is lost? ____________, ____________, and ___________

5. How is ice removed from the airframe? ________________________

6. When are engine covers removed on the pre-flight inspection? __________________

7. Does hot oil warm the engine? ________________ Why?________________________

8. If you are the first one to fly the aircraft in the morning, what must you do the night before?________________________

9. Describe engine priming: How many strokes?__________. How much time between strokes? _________ How long after the last stroke before engaging starter? _________. Why? ___________________________________

10. What does 'pumping the throttle' do?___________________________________

11. Should the 'FIELD' switch be on or off during engine start? ___________

12. What should be your action is the engine misfires on start-up? ___________________

13. How long should you wait before adding higher power to a cold engine after start-up? _____________________________

14. What is the purpose of carb heat on start-up?__________________

15. What is a draw-back of using carb heat at any time? ______________________

16. What is the risk of carburettor ice on a cold day?_________________________

17. How can propellers be damaged on start-up and run-up? ________________________

18. Describe what you expect to get from the fuel drain on a cold day. _________________________________________________________________

19. How many seconds should it take on the runway to reach full power from idle power? ________________________

20. What power setting is used for the descend on a cold day? ___________________

21. Does an engine tend to run richer or leaner on a cold day? ___________________

22. How does 'leaning' change cylinder temperature? _________________________

23. What role do flaps play on a cold day? __________________________________

24. How is frost removed from the windshield? ______________________________

25. What particularly is important to check if there has been a cycle of snow, melting, and freezing? _______________________________

26. How would you expect oleos and tires to look on a cold day compared to a warm day? _______________________________________

27. How does battery capacity on a cold day compare to its capacity on a warm day?____________

28. How do you prevent frost from forming on the inside of the windshield after start-up? _________________


Français

Les prochaines questions sont basées sur des informations présentées lors du “Séminaire vol en hiver” du 18 novembre 2008. Il est impératif aux pilotes de connaître la réponse à ces questions.

Un pilote doit obtenir un minimum de 90% de bonnes réponses à ce test pour être autorisé à piloter un aéronef appartenant à Laurentide Aviation lorsque la température est sous 0°C.

Dans tous les cas, le présent test doit être corrigé à 100% avec l’aide d’un instructeur.

L’enjeu : la sécurité des opérations et le coût des opérations.


1. Combien de temps avant le démarrage doit-on avoir branché le chauffe-moteur? __________________________________________________________________

2. Quel moteur de l’aéronef ne doit absolument pas être démarré s’il n’a pas été branché au chauffe-moteur avant le démarrage? __________________________________________________________________

3. Que doit-on spécifiquement vérifier sur les roues (« spinners ») durant l’hiver? __________________________________________________________________

4. Quelles sont les trois façons de perdre de la chaleur? _____________________, ____________________, et _____________________

5. Comment enlève-t-on de la glace de la cellule (« airframe »)? __________________________________________________________________

6. À quel moment enlève-t-on l’enveloppe de moteur lors de la vérification pré-vol? __________________________________________________________________

7. Est-ce que de l’huile chaude réchauffe le moteur? _________________________
Pourquoi? _________________________________________________________

8. Si vous êtes le premier à voler avec un aéronef le matin, que devez-vous absolument faire le soir? _________________________________________________________________

9. Décrivez l’amorce (« priming ») du moteur: Combien de coups de pompe d’amorçage (« primer »)? _______________
Combien de temps doit-on laisser entre chaque coup de pompe d’amorçage (« primer »)? _____________
Combien de temps après le dernier coup de pompe d’amorçage (« primer »)doit-on attendre avant de faire partir le moteur avant de démarrer? _____________________________________
Pourquoi? _________________________________________________________

10. Qu’est-ce qui cause de pomper la manette des gaz (« Throttle »)? __________________________________________________________________

11. Est-ce que l’interrupteur « FIELD » doit être « ON » ou « OFF » durant le démarrage du moteur? __________________________________________________________________

12. Que devez-vous faire si le moteur fait une pétarade (« misfires ») au démarrage? __________________________________________________________________

13. Combien de temps devez-vous attendre avant de mettre pleine puissance à un moteur froid après le démarrage? __________________________________________________________________

14. Quel est le but de mettre le réchauffage de carburateur (« carb heat ») au démarrage? __________________________________________________________________

15. Quelle est la contre-indication à utiliser le réchauffage de carburateur (« carb heat ») en tout temps? __________________________________________________________________

16. Quel est le risque d’avoir un carburateur glacé lors d’une journée froide? __________________________________________________________________

17. Comment peut-on endommager l’hélice au décollage (« run-up »)? __________________________________________________________________

18. Décrivez qu’est-ce que vous êtes censé découvrir lors de l’inspection du purgeur (« fuel drain ») lors d’une journée froide? _________________________________________________________________

19. Combien de secondes devez-vous prendre lorsque vous êtes sur la piste pour aller de bas régime à pleine puissance? __________________________________________________________________

20. Quelle est la puissance qui devrait être utilisée pour atterrir lors d’une journée froide? __________________________________________________________________

21. Est-ce qu’un moteur doit rouler sur une mixture en essence plus riche ou plus pauvre lors d’une journée froide? __________________________________________________________________

22. Pourquoi l’appauvrissement de la mixture en essence change-t-elle la température des cylindres? __________________________________________________________________

23. Quel est le rôle des volets lors d’une journée froide? __________________________________________________________________

24. Comment enlevez-vous le givre d’un pare-brise? __________________________________________________________________

25. Qu’est-il particulièrement important de vérifier s’il y a eu un cycle de température neige, fonte de neige et gel? __________________________________________________________________

26. Comment devez-vous présumer quels seront les amortisseurs oléopneumatiques (« oleos ») et les pneus lors d’une journée froide par rapport à une journée chaude? __________________________________________________________________

27. Quelle est la capacité de la batterie une journée froide comparé à la capacité de la batterie une journée chaude? __________________________________________________________________

28. Comment faites-vous pour éviter la formation de givre à l’intérieur du pare-brise après avoir démarré? __________________________________________________________________

29. Où peut-on trouver la Charte de correction de l’altitude pour température froide? __________________________________________________________________

30. Quel est le poids d’un gallon de gazoline à -20°C? __________________________________________________________________

English test

Top of Page

Frank Hofmann
Copyright © 2003