“Is it supposed to look like this?” the pre-solo learner asked, pointing to the right wingtip of the Cessna 172. The wingtip light was askew, hanging by a wire and a piece of what looked like duct tape. Someone or something had whacked that wing tip hard. There was some paint transfer and a scrape on the underside of the wing. This first-flight-of-the-morning discovery turned into a lesson on what to do when you find damage to the airplane.
The learner was very concerned that he would have to pay for the repair because he found the damage. That’s not how this works, I assured him, wondering out loud how many times the airplane had flown like that, and if another pilot had noticed the damage but not reported it for fear of being blamed and billed for it.
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The event resulted in a new flight school policy: All renters shall perform a postflight inspection specifically to make sure the aircraft was not only tied down and locked up, but also damage free. Any damage shall be documented and reported to the staff.
Preventing Mystery Damage
Mystery damage is the bane of flight schools. It takes many forms. It is the crack that appears in the fairing on the wingtip. The tailguard knocked askew during a bad landing. Flat spots on the tires from excessive braking. Or they can be more severe, like a U-shaped crack in the back window caused by an unsecured tow bar during an unsanctioned zero-G maneuver.
The damage often isn’t reported, as the low-time pilots don’t have the experience to know what is normal wear and tear and what is significant damage enough that it could potentially render the aircraft unairworthy or be a symptom of a bigger problem. When mystery damage is discovered, it often starts an investigation at the flight school.
The in-house investigations usually begin with a review of the dispatch book for the aircraft. The last pilot who flew it is questioned: “Did you notice [insert type of damage here]?” Some pilots can get very defensive, announcing loudly that they didn’t do it, therefore, they won’t be paying for the damage. But the truth be told, they really aren’t 100 percent sure if the damage was the result of their flight—because they didn’t do the postflight inspection. A postflight inspection takes just a few minutes and does wonders for your peace of mind. Let’s review some common scenarios.
Sloppy Securing Raises Questions
How many of you can relate to this: You head out to the rental aircraft and find it hasn’t been properly secured? The door is unlocked or the tail isn’t tied down, or the control lock is missing or the cowl cover is flapping free in the breeze because someone didn’t buckle it properly? When you find something askew with the aircraft, it can make you wonder what else the previous pilot skipped and why.
Check the Numbers
How many times have you had to go back out to the airplane to double-check the Hobbs or tach number because you forgot to get the information, or the numbers as put into the dispatch program didn’t make sense?
Checking the Hobbs and tach against what is recorded in the dispatch book should be part of both the preflight and postflight inspection because if the Hobbs meter fails—and it does—you have to multiply the tach by 1.3 to get the billable time numbers. Pro tip: Write down the time of engine start and engine stop, or use a stopwatch to get accurate metrics. This technique is also used to determine fuel consumption, so practice is important.
Claim the Number
During the postflight check of the numbers, be ready to “claim” the next number if it is coming into view on the Hobbs meter. For example, if you can see the “8” starting to roll into the window, put down eight in the dispatch book. This is just good manners, because the next pilot will be paying for that tenth of an hour that you used as the eight will roll into the window likely at engine start. Failing to do this is the aviation version of putting an empty milk carton back in the fridge.
Postflight Fuel Check
There are some flight schools that require a postflight fuel level check and a recording of it in the dispatch book. There may be an agreed upon minimum fuel such as 16 gallons, or the rule may be that each CFI checks the level prior to the learner arriving for their lesson and then arranges for refueling to take place.
Some flight schools are so busy it doesn’t make sense to refuel after every single flight, or there may be a “weight restrictive” flight in the schedule. The latter should be documented in the aircraft reservation schedule and a note placed in the dispatch book. It’s a lot easier to add fuel to a minimum level for the flight than to pump fuel off. There are some flight schools that don’t have the equipment to remove fuel, so in a pinch they may send one of their CFIs out to fly approaches for an hour to reduce the fuel load.
Shutdown Slips
The postflight inspection can reveal when an aircraft has not been shut correctly—for example, the mags left on or the carb heat knob left out. This is a slip and one of the reasons you should always check the position of the mags before approaching the propeller arc.
Sometimes a student pilot gets confused on how to secure an aircraft, and then you have to track down who is improperly shutting down the airplane and educate them. For example, there was a time when pilots at a particular flight school kept finding a particular Cessna 172 tied down and chocked with the mixture knob in the full forward position.
The mixture knob is supposed to be at idle at shutdown. Putting the mixture knob to full rich puts fuel into the system the same way the manual primer does. A little bit of sleuthing revealed this (incorrect) practice was being done by a student pilot who thought he was saving the next pilot a “step.”
The most common postflight mistake that can be thwarted by a postflight inspection is leaving on the master switch. In fact, as I write this, I am waiting to hear if the battery on the airplane I am supposed to fly later has been recharged or replaced as it was left on after a night flight. At many schools there is a fee for leaving on the master switch—like $100 and a case of beer for the maintenance team.
Checklist, Fuel Strainers, and Keys (Oh, My!)
Before you walk away from the airplane, make sure the tools used for the preflight inspection, such as the fuel strainer and pipette, are stowed in the previously agreed on location. Make sure the checklist and the aircraft keys are back in the dispatch binder. While most schools have spares of these items, especially the checklists and keys, you do not want to be that renter who accidentally walks off with these items.
Before you walk away from the airplane make sure the dispatch book has the keys and checklist stowed. If the checklist or keyring is falling apart, let the school know so it can make repairs. It just takes a few minutes and can prevent these items from disappearing.
Squawks
When there is a discrepancy or malfunction with an aircraft, it is written up in a procedure known as “squawking.” If you find something that may be damaged, but you are not sure if it is, or if it happened during your flight, write it up. You may find out that it is “old damage” (which tells you that you should pay closer attention during your preflight inspection), or you may have uncovered an issue that if not noticed could have resulted in an expensive repair or unscheduled off-airport landing.
For example, one private pilot noticed a puddle of oil beneath an airplane that had just returned from a flight. The oil level had been low prior to takeoff so the pilot, following the checklist with the notation never to fly with less than 6 quarts, added a quart. During the postflight inspection the pilot noticed the aircraft was now down to 5.5 quarts, and a closer inspection of the engine compartment revealed a greasy mess and a swath of oil down the aircraft’s belly. The mechanic diagnosed a cracked tube and noted that if the pilot who found the issue had flown for more than an hour, the airplane might have developed a serious engine issue from lack of oil pressure.
Because you don’t know what you don’t know, always err on the side of caution. A postflight inspection can go a long way.
This column first appeared in the May Issue 958 of the FLYING print edition.
