The FAA recognizes the significant challenges that night flying puts on pilots through the night currency requirements in the federal aviation regulations. (FAR 61.57(b) requires three takeoffs and three full-stop landings within the preceding 90 days in an aircraft of the same category, class, and type.) Readying the aircraft for night flying is just as important.

Setting a baseline

Flying at night heightens the senses. The slightest engine vibration, stumble, or operational variation can quickly become the focus of a flight that would otherwise seem routine if flown in daylight. Understanding your aircraft’s baseline can help you distinguish between real and perceived anomalies. On your next daytime flight, take the time to focus closely on the key parameters that may cause concern at night. Specifically, take notes on the following:

• Engine speed drops during runup.
• Maximum static revolutions per minute prior to brake release on takeoff.
• Climb rate during initial climb.
• Exact fuel flow during full-rich climb and leaned cruise flight.
• Any rpm changes caused by propeller adjustment or during fuel tank switching.
• Bus system voltage and amperage draw (with and without all lights on).
• Fuel and oil pressure.
• Cylinder head temperatures and oil temperatures.
• Landing gear retraction and extension times.

Keep these notes on your kneeboard or somewhere that you can easily reference in flight if you are questioning an anomaly. If any of these parameters are out of spec for your aircraft, reach out to your mechanic and get everything in line before flying at night. Be sure to download the latest engine data in case you need to have it analyzed.

Electrical system maintenance

The health of the aircraft’s electrical system is a key differentiator between day and night flying, as an electrical failure that might be a nuisance during the day could easily become an emergency at night.

The most important component to check is the aircraft’s main battery. I like to think of the health of the battery in terms of its capacity, which is similar to fuel in the tanks. If the alternator fails, the battery’s capacity is what will get you safely on the ground at night with the lighting and communication you need. Every battery should be tested annually on a calibrated capacity tester, and I recommend that this be performed prior to beginning routine night flying during the winter months. This simple test demonstrates the battery’s actual ability to deliver power and a high current draw, similar to what you would experience during an alternator failure. Not only is it required by battery manufacturers in their instructions for continued airworthiness (ICA), but it also establishes exactly how much time you have to reach a safe destination if your battery becomes the only source of electrical power.

I also recommend adjusting your voltage regulator for winter temperatures. As with the capacity test, battery manufacturers recommend different bus voltages be used for various average outside air temperatures (see your battery owner’s manual for details).

Lighting

The most obvious maintenance aspect of night flying is aircraft lighting. Every exterior light on the aircraft, including the exterior landing, taxi, navigation, strobe, and beacon lights, should be tested. This is best done with two people: one outside the aircraft verifying proper operation, and the other inside the aircraft operating the switches and monitoring the ammeter for any unusual current draws. It’s not uncommon for exterior lighting to develop high resistance from corrosion at the bulb or socket electrical connectors. Any strong current draw should be investigated, and the contacts can be easily cleaned with electrical cleaner and a Scotch-Brite hand pad if required. (White pads are superfine grit and the safest to use; gray pads are fine grit; and maroon pads are medium grit, which is generally too aggressive for delicate, plated connectors.)

Interior lighting is just as important and is often overlooked. Be sure to test all panel lighting, map lights, and avionics lighting. This includes replacing any broken post lights, internal compass lights, or instrument bezel lights. The dimmers that operate the lights should also be tested throughout their range to ensure there are no dead spots during the dimming process. Lastly, check the avionics lighting settings and make sure you are familiar with their operation so that the panel is properly lit for legibility without affecting your night vision.

Preflight

Preflighting an aircraft at night is very challenging. Not only is it easy to miss something when your vision is limited to the range and focal area of a flashlight, but colors become muted, making it difficult to tell the difference between brown oil, red hydraulic fluid, blue fuel, and clear water. If at all possible, perform a very thorough preflight during daylight hours, followed by a more streamlined night preflight just prior to takeoff. Also, be sure to move the aircraft during the preflight to look for signs of leaks on the ground and to inspect the full circumference of the tires. Give yourself plenty of time for your eyes to adjust after using a flashlight during the preflight before taking off.

Emergency preparations

Similar to the main aircraft battery, all other batteries in the aircraft should be tested, charged, or replaced prior to night flying. This includes flashlights, headsets, portable radios, carbon monoxide monitors, portable ADS-B devices, phones, and tablets. Spare batteries should be easy to find, remove from their packaging, and install in a dark cockpit.

Emergency communication is especially important at night, so I recommend having a portable radio available and ready to use if required. You should be able to plug your headset directly into your portable radio and be very familiar with its operation. I’ve seen some aircraft wired with a dedicated antenna cable built into the aircraft panel to allow a portable radio to patch into the aircraft's external antenna. This can make all the difference when trying to reach someone on the ground, given the low output power of most portable radio transmitters. Ask your mechanic or avionics shop whether this is a reasonable upgrade for your airplane.

Night flying can be extremely rewarding and fun, but it takes preparation to be performed safely. Take some time to get your aircraft ready for the season, implement a solid night-preflight routine, and stack the odds in your favor. Until next time, I hope you and your families remain safe and healthy, and I wish you blue skies.