Twin Bonanza Fuel Boost Pumps are either Pesco P/N 122723-112-01 or Adel P/N 56881-1. You could have either of them on your aircraft. They can be identified by removing the inspection plate below the pump and looking at the data plate before ordering. CAUTION! NEVER RUN YOUR BOOST PUMPS UNLESS SUBMERSED IN FUEL.

At one point or another, we are faced with having to replace a boost pump. When this occurs, the task is carried out by your mechanic. Unfortunately, when the overhauled pump is being prepared for installation, some unknowing mechanic might get the bright idea that he wants to see if the pump motor turns, before going to the trouble of inserting it into the tank bottom and making the necessary electrical connections. In doing so he'll connect it up to an external power source and run the motor – When he does so, he is running it dry and there is a very good possibility the he has ruined one of the major seals.

Save yourself some grief by telling him in no uncertain terms that he should never hook up power to this unit unless it is immersed in fuel. Be certain that even once the pump has been installed in the aircraft that they do not apply power unless some gasoline is placed in the tank. We became aware of this occurrence when a fresh unit was returned because the seal leaked. When finally speaking to the mechanic, he admitted that he ran it DRY on the bench. Bingo!

I know some of you already have this policy, but if there is a way that you can gain permission to work along with your mechanic during maintenance operations of your Twin Bonanza, it can save you many dollars and grief. The Twin Bonanza like all aircraft, takes special knowledge in certain areas. It is helpful to the mechanic very often, when an owner relays this information on to them, as work progresses. If a request to do so is offered and performed in the right spirit, very often owner assisted maintenance is even welcomed.