Learning the Differences

Learning the Differences

Learning the Differences

The challenge is figuring what is unique or different about a new-to-you airplane, then applying that information in some practical fashion.

One of the companies I fly for recently acquired a Gulfstream 150, and over the past several months, our pilot group (mostly accustomed to flying lighter Learjets and Citations) has been getting checked out in the new machine. Two in the group spent a couple of weeks and $40,000 each completing the full simulator training course. The rest of us took the ground school course the aircraft management company put on, then completed flight training in the airplane itself – leading to a 61.55 check ride and a second in command rating. I have been through this process several times over the years, and starting to get the ritual down pretty well. 

You would think the main challenge in approaching a new or different airplane would be the “flying” part. Perhaps crosswind landings, V1 cuts or other such maneuvers. But at least for me, that is not the case. This is probably because with time, you come to realize that all airplanes are similar in the way the controls work, and they also have a lot of operational limitations in common. For example, just about all small corporate type jets have an engine starting wind limitation of 10 knots if the engine’s intakes are facing downwind. Another example is the operation of windshield heat is usually prohibited while on the ground. The challenge is figuring what is unique or different about a new-to-you airplane, then applying that information in some practical fashion. 

The G150 nose wheel steering system has a pin that is pulled when parked and must be re-inserted before taxi, a task that is sometimes easier said than done.

Recognizing this is where the challenge lies, the ground school emphasized to us the differences in a G150 – and there are quite a few of them. Most may seem relatively minor or petty in the large scheme of things, but they are nevertheless important from a practical point of view. For example, somewhat surprisingly, the first and most important thing for any experienced professional corporate pilot to master is the the cabin door. If the passengers see the pilot stumbling over the everyday act of opening or closing the door, they automatically assume his or her piloting skills must lack, and everything else that subsequently occurs during the flight will be interpreted through that negative lens. And the G150 has a couple of real “gotchas” when it comes to the door. 

First, the door is big and heavy, hinging onto the bottom of the fuselage. There is a flush-mounted handle at about eye level that operates a lever that turns and pulls all the locking pins holding the door. Once unlocked, a pretty hefty tug makes it start to drop down, and the tendency is to try and cushion its descent with your hand because you are standing right under it. But, it turns out the door has hydraulic cylinders that limit the rate of descent, and if you are pushing against them, the door simply won’t drop down. The act can leave you standing there holding the door up and looking like an idiot in front of the passengers. So, the drill is to pull the handle, give the door a good yank, then get out of the way while it descends all by itself. 

The door stops its automatic descent when it is about 6 inches from the ground and hangs there while a rubber-tipped foot drops down to the ground to support the door while passengers ascend the stairs. The problem is if the airplane is light, say with half tanks or less, it sits higher on the landing gear and the rubber-tipped foot does not touch the ground. Consequently, if a heavyset passenger puts all their weight on the first step, the door can overextend the hinge attached to the fuselage, bending the metal and effectively grounding the airplane on the spot.

Key pilot memory item: don’t forget to retrieve the wood block that keeps the door from overextending during passenger boarding.

To prevent this disaster caused by “pilot oversight,” a 4-by-4-inch block of scrap wood is kept near the door entry. It is the pilots’ job to make sure that piece of wood is placed under the rubber stop before anyone is allowed to board. Upon departure, the pilot (in addition to dealing with IFR clearances, fuel and baggage loading) must also remember to retrieve that piece of scrap wood before the door is closed. If forgotten, it can cause all kinds of turmoil at the next stop. It is indeed peculiar that a piece of scrap wood is an operational necessity in an airplane costing $14 million, but it is a difference that must be learned and demonstrated before a new pilot checkout. 

Once you master the door, it is time to move on to other things. On nearly all small jets, the batteries are typically disconnected from the aircraft before it is parked because there are hot battery bus items that can discharge them overnight. But on the G150, they are in the back of the airplane and inaccessible to the pilot during preflight. So, after opening the door, the pilot’s next job is to turn on the master switch and see how much power remains in the batteries. It must be 24 volts or better, but don’t sit and stare at the display too long after turning the master on. The batteries will deplete and you won’t be able to start the APU, effectively grounding the airplane unless ground power is available. 

Starting the APU has its own ritual. First, you must check the unit’s fire suppression system by pressing the half-inch square arm or test switch on the center of the instrument panel, all the while taking great care to keep your other finger off the discharge switch of the same size immediately next to it. If you accidentally push that switch, the bottle will discharge and ground the airplane until the mess can be cleaned up and the fire bottle re-charged. Then comes a test for fuel availability to the APU, which comes from the right engine supply. If this is good to go, the APU itself can finally be started with the push of a button. The little jet engine starts almost right away. With a lot of small jet APUs, there is a required delay of a couple of minutes to allow the engine to warm up before the generator and ECS (environment control system) is switched on. But on the G150, while there is a two-minute delay only on the ECS, the generator can come on right away. All kinds of funny little differences to remember that have very little to do with actually flying the aircraft.

Now with the little jet engine roaring away in the back and the ECS warming the cabin, it is time to actually do the walk around part of the preflight. This involves the usual steps like making sure the tires are inflated, but there are also a couple of peculiar exceptions that must be dealt with – one of which is the nose wheel steering system. The nose wheel has a pin that must be pulled when the airplane is parked, completely disconnecting the wheel from its control linkage. It must then be re-connected before any attempt (other than a very embarrassing one) is made to taxi the aircraft. Re-inserting the pin, however, turns out to be best completed by both pilots as the dual nose wheels often need to be moved slightly for the pin’s holes to line up. This requires grabbing the tires with both hands and twisting them slightly in order for the pin to line up correctly. But with both hands busy, it makes placing the pin nearly impossible if a pilot is doing the preflight by himself. So, it is not uncommon to see two G150 pilots getting their pants dirty while crawling under the airplane near the nose wheel. Learjets don’t share this issue, which is one reason we had to pay special attention to it during the G150 checkout.

After ensuring all the sneaky preflight items are completed, it is time to board and start the engines. However, before actually pushing the “start” buttons, you must first work your way through a 45-item checklist, including everything from the coffeemaker to the fire extinguishing system. Once that is complete, starting the engines just requires the push of a single button once the power levers are placed in the idle position. With the engines running, there are 17 more items to check and you are finally ready to taxi. But, don’t be too quick about releasing the brakes. The rudder pedals only control the first 3 degrees of nose wheel movement. The remaining 60 degrees of turn is managed by a small steering wheel on the left side of the cockpit (similar to most airline aircraft). The steering wheel itself has an on/off switch, so make sure that switch is on before advancing power. With only 3 degrees of movement via the pedals, you will almost certainly hit the hangar door even with your foot on the rudder buried right to the stop. 

After successfully taxiing out, we run a series of other checklist items fairly common to small jets (such as cycling the spoilers) and get to the lineup portion and takeoff briefing. The main difference here is only the pilot in the left seat of the G150 has good directional control of the aircraft during the initial portion of the takeoff roll – and he does this using his left hand on the small steering wheel and right hand on the throttles. So, if the left seat pilot is the one flying, the control wheel must be properly positioned and held for the wind conditions by the pilot in the right seat until sufficient speed is reached (usually about 80 knots). At that point, the left seat pilot releases the small steering wheel with his left hand, places it on the control column and announces “my wheel.” Shortly after that, V1 is called by the monitoring pilot and the pilot flying releases the throttles and places both hands on the control column. This is a common practice in airline aircraft, but not required in lighter jets like Lears. The process takes a few takeoffs to get the teamwork down but comes fairly quickly when briefed in advance. 

Once V1 is reached, the G150 landing gear requires a fairly heavy pull on the control column to get the nose wheel off the ground and the aircraft pitched up. Shortly after, the back pressure must be released or the nose will point toward the heavens with the climb rate going to 4,000 fpm. Despite being briefed on this detail, I take way too long to release the back pressure to get the nose down on my first takeoff. In Learjets, if you lower the nose too much, you will almost certainly get an over-speed warning as you blast through 250 knots. Yet another slight but significant difference to remember.

Once airborne, we perform a series of maneuvers then return to do some landings. With a trailing beam gear, a very gentle landing in the G150 is certainly possible. But, this is to be avoided if the runway is on the shorter end because the spoiler deployment system will not be activated until weight on the wheels is fully established. So, the idea is to “put it firmly on the ground” unless you have a couple of miles of runway. Then, as the landing roll slows down, make sure to remember the nose wheel control is again switched to the left seat pilot, who then taxis the airplane back to the ramp while the right seat pilot runs the after landing checklist. Ah, more differences.

When I was in my 20s and a new flight instructor, I routinely told new students, “All airplanes basically fly the same, and the bigger they are, the easier it is.” And, in a certain way, I still believe that to be true. But on the other hand, 11,000 flight hours and multiple type ratings have taught me that it is true only if the word “fly” is narrowly defined. Although all airplanes essentially fly the same, their operational complexity increases almost directly with the maximum takeoff weight. Plus, all have design differences peculiar to the manufacturer that sometimes leave you wondering, “What were they thinking?”

It is the differences that you have to pay attention to.  

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