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Beechcraft Travelair

The Beechcraft Travelair

On Sheble’s website, they have a pdf document that helps you prepare for flying the Beechcraft Travelair BE-95 Light Twin.  For the sake of this website, I’ve taken that document, cleaned it up, and added to it, so I can use it during my training.

Here are the basics….The Beechcraft Travelair is a light twin-engine airplane that has the same basic fuselage as the Beechcraft Bonanza.  It fills the gap between the Model 35 Bonanza and the much bigger Model 50 Twin-Bonanza.  Beechcraft airplanes are well built, and in their review of twin engine accidents, aviation consumer found that Barons (as compared to Cessna 310s and 421 and Aztec Apache/Navajo airplanes) had the fewest maintenance-related crashes — indicating that the airplanes are well-built and don’t break much.

Beechcraft Travelairmulti engine ratingtwin engine instruction

The Beechcraft Travelair is one of those airplanes that sort of illustrates the adage about light twins: Two engines double the changes that something will fail, and when it does, the remaining engine only has enough horsepower to carry you to the site of the accident.  In a recent review of 545 accidents in light twins, aviation consumer (http://www.avweb.com/news/safety/185267-1.html) concluded the following:

  • Having reviewed the accident database, we conclude what most rational owners already know: A well-maintained twin with a current, well-trained pilot is probably safer than a single, provided it isn’t flown over gross weight. The safety accrues, of course, from an additional engine with dual vacuum pumps and dual alternators.
  • If one engine fails, a competent pilot has real, not illusory, options by having meaningful backup systems to fill in until the airplane can be landed safely on one engine. The accident record seems to suggest that a pilot who’s overtaxed by a system or engine failure is less likely to survive in a twin than in a single.
  • For that reason, in our view, on safety issues alone, an owner contemplating upgrading to a twin shouldn’t consider the proposition unless there’s enough money in the kitty to maintain the airplane to the highest reasonable standards and to both fly often and train often. To do less probably results in an overall reduction in safety.

Sheble is a bit more brief.  Their multi-engine preparatory information states that in general,

  • Light twin are typically more complex, but not excessively.
  • They require more cockpit management tasks and memorized procedures, especially engine out procedures.

However, in the hands of an appropriately trained and competent pilot, the increased performance and the ability to maintain level flight and climb under certain conditions does increase the margin of safety.  Their opening line is as follows: Those multi-engine pilots who do not know the engine out procedure off hand or have a lackadaisical attitutude toward the procedure are not competent multiengine pilots.  KNOW THE PROCEDURE.

Since we are in fact preparing for a checkride in this process, I read over the Sheble’s information and added to it by researching some of the specifics on the Travelair on line.

The Fuel System

There are 4 tanks in the Beechcraft Travelair, with a total capacity of 112 gallons.  Fuel burn for rough calculations is 20 gallons per hours total, 10 per side.  There are 4 fuel pumps, 2 that are engine driven and 2 electrical boost pumps and 8 fuel drains.  The 8 drains are for the following components of the fuel system:

  • 4 tanks (2 main and 2 aux) with a drain each =’s 4 drains
  • 2 crossfeed drains
  • 2 low point drains

The fuel system on twin engine aircraft does require particular attention during the transition period.  There are a surprisingly large number of twin engine aircraft crashes related to a basic misunderstanding of the fuel system.  To quote, “some pilots kill themselves by simply not understanding the aircraft systems, chiefly the fuel plumbing. Mismanaging fuel crossfeed during single-engine drills can turn a ho-hum proficiency exercise into a genuine no-engines survival struggle. It seems obvious that if a pilot loses one good engine due to fuel mismanagement, he stands a good chance of losing the other when trying to right the situation.”

So, If you are in need of a more complete description of the Beechcraft Travelair fuel system, here is what I learned online….

The Beechcraft Travelair fuel system consists of a separate identical fuel supply system for each engine. Each wing contains one Main tank and one Auxiliary tank (Aux.)  The fuel tanks are lined with a rubberized fuel cell. These cells are quite sturdy under normal service conditions but care must be taken to avoid puncturing the cell. Do not use a dipstick to check fuel quantity; instead perform a visual check and crosscheck with the fuel gauges and fueling records to determine the amount of fuel onboard. The Main tanks are particularly easy to check visually.

The auxiliary tanks slope, due to the wings dihedral, so that no fuel is visible at the filler neck when the tank’s quantity drops below ¾ full.  Each fuel tank is filled through its own filler neck. The fuel caps have O-rings to prevent water from entering the tanks. All fillers must be checked to confirm they are securely closed before flight.  The Main fuel tanks hold 25 US-gallons with 22 gallons useable. The Main tanks must be used for all takeoffs and landings. Main tanks should normally also be selected when performing special flight maneuvers such as stalls.

The Auxiliary tanks hold 31 US-gallons with all 31 useable. The auxiliary tanks may be used in normal climbs, cruise and descents. Auxiliary tanks should not be used when performing steep turn, slips, stalls, or other unusual maneuvers unless they are at least ¾ full.

Fuel quantity is measured by a float type transmitter unit in each tank that sends a signal to fuel gauges on the Power gauge panel (see below.) There are two fuel gauges, controlled by a two-position switch on the Pilot sub-panel.  The switch can be set to Main or Aux and displays the quantity of the two main tanks or the two auxiliary tanks respectively.

Each engine has an engine-driven fuel pump driven by the engine accessory box. The engine-driven fuel pump supplies sufficient fuel to the engine for full power operation.

An electric boost pump for each engine supplies fuel pressure for starting and provides for near maximum engine performance should the engine driven pump fail. The electric boost pumps are used to prime the engine for starting and in emergencies, and should be used for takeoff and landing. In extremely hot weather they should be employed for all ground operations, takeoff, climb, and landing.

The electric boost pumps are located in the fuel lines between the fuel cells and theand the engine such that fuel may be drawn from any tank using the boost pumps.  — and here’s a picture..(click to enlarge)

multi-engine-fuel-system

The Electrical System

The Beechcraft Travelair has a 28 vol system with 2 12 volt batteries in series to create a 24 volt system.   The battery is recharged by two belt driven 55 amp alternators.  The two electrical system supplies two separate bus bars (and in case you want a full definition, a bus bar is a strip of copper or aluminium that conducts electricity within a switchboard, distribution board, substation or other electrical apparatus), one that distributes 12 volts for the avionics and the other that sends 24 volts to the other electrical equipment including the flaps, gear, and lights.

The Landing Gear

The landing gear on the Beechcraft Travelair is all electric.  It is an electrically operated tricycle landing gear operated through push-pull tubes by a reversible electric motor and actuator gearbox under the front seat. A two-position landing gear switch located on the right hand side of the center console controls the motor. Limit switches and a dynamic braking system automatically stop the retract mechanism when the gear reaches its full up or full down position.

Aviation consumer notes that in their analysis of twin engine accidents the Beech Baron series has a dramatically higher number of gear-up and inadvertent gear retractions than do the other models. This is due in part, in our view, to the fact that in the early models, Beech put the gear switch to the far right and the flaps on the left, the reverse of the industry standard.

We also noted that the more complex twins — the Cessna 421 and Cessna 310 — seem to have a larger percentage of maintenance-related accidents than do other models. The Apache/Aztec series shared this dubious distinction, perhaps more due to aging airframes than complexity.

Propellers

The Beechcraft Travelair has full feathering hartzell propellers.  High oil pressure drives the props to a flat pitch / high RPM position, whereas complete loss of oil pressure will drive the props to the feather position.  When the engine RPM drops below 800, locking pins prevent the props from feathering when the oil pressure drops at engine shut down.  This is so that the next time the engine starts it doesn’t have to push a feathered blade around in a circle, adding to the resistance of getting the engine going and creating a lot of vibration.

A nitrogen driven oil accumulator on each engine contains a reserve of pressure that will allows the props to be unfeathered inflight during a restart procedure.  This accumulator is necessary because during unfeathering, there is no oil pressure from the engine to drive the prop to a flat pitch so energy stored in the form of compressed nitrogen gas is used to change the angle of the blades.

Vacuum pumps

  • Each engine has its own vacuum pump for the gyroscopically driven flight instruments.

Hydraulic systems and Flight Controls

  • The brakes and the propellers are hydraulically actuated.
  • Primary and secondary flight controls are all standard pulley and cable connections

And the Beechcraft Travelair has the usual panel layout for an older steam gauge airplane.

The POH for a twin engine has got a couple of new items, and for the sake of a review, I collected a list of all of the V speeds that I’ll need in order to pass this checkride.  The list of appropriate V speeds for twin engine training is as follows, and I’ve got in a pdf document that you can print out and fold in half and slip inside a normal Jepp chart protector

Va     Maneuvering Speed is the maximum speed which you may use abrupt control travel.
Vfe    Maximum Flap Extended Speed is the highest speed permissible with flaps extended.
Vle    Maximum Landing Gear Extended Speed
Vlo    Maximum Landing Gear Operating Speed max speed at which the gear position may be changed.
Vno    Maximum Structural Cruising Speed is the speed that should not be exceeded except in smooth air, then only with caution.
Vne    Never Exceed Speed is the speed limit that may not be exceeded at any time.
Vs   Stalling Speed or the minimum steady flight speed at which the airplane is controllable in cruise configuration.
Vso    Stalling Speed in the landing configuration at the most forward CG
Vx    Best Angle of Climb Speed is the speed that results in the greatest gain of altitude over distance.
Vy    Best Rate of Climb Speed is the speed that results in the greatest gain of altitude in a given time.
Vxse    Best Angle of Climb Speed on Single Engine.  Failed engine is feathered.
Vyse    Best Rate of Climb Speed on Single Engine.  Failed engine is feathered.  (BLUE LINE)
Vmc    Minimum Single Engine Control Speed: see this link Vmc explained
Vsse    Intentional One Engine Inoperative Speed

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