Everyone Should ALWAYS use Boost Pump on takeoff
First off, my apologies for this slight thread hijack. Moderators should feel free to remove this post if they feel it does not contribute to this thread.I cannot help but notice your comment seems to imply that EVERYONE should ALWAYS be taking off with the boost pump on. Just to give a data point for consideration, my engine will not idle with the boost pump on. It will flood out and die. Perhaps it is possible I could flip the switch for the boost pump on during the takeoff roll once I have gone full throttle, in which case, the engine most likely will not flood out but that sure introduces an additional task to perform during a very critical and busy point in the flight. This procedure would also require an additional step during cruise initiation to turn OFF the boost pump. For sure, I would not want to have the boost pump on during any other time except during full throttle applications.
In my risk analysis of the takeoff event, I believe this procedure would be a higher risk than not having the boost pump on at takeoff. The reason being is that it would introduce human errors into the take off and climb out that could be just as dangerous, and perhaps more so, as would having a mechanical pump failure. Although I see the mechanical fuel pump failure as a HIGH risk failure if it occurs, it is offset in my analysis by the fact that this type of failure would be a low probability event. On the other hand, my forgetting to turn OFF the boost pump after full throttle application could also be considered a HIGH risk failure but it would have the added danger of also actually being a high probability event, especially considering how well I understand my own human failings when it comes to remembering things.
Because of the high probability of failing to switch OFF the boost pump when needed, I would consider this event a HIGHER risk task than taking off with only the mechanical fuel pump. It is more likely that I would forget to turn off the boost pump than it is likely for the mechanical fuel pump to fail. Therefore, I choose to mitigate the risk of the high probability event. As for the low probability, but potentially high risk event of the fuel pump failure, well, I do have a boost pump switch ready to flip in a heartbeat's notice less than a quarter of an inch away from my right hand that is grasping the throttle knob.
My checklist for this failure might go something like this:
- Feel engine sputter
- Push nose down
- Fly the airplane
- Reach up quarter of an inch from throttle with right hand index finger and flip on the fuel boost pump
- Fly the airplane
- Wait for fuel to ignite again in engine
- Fly the airplane
- If engine reignites make haste to the nearest safe landing area
- Fly the airplane
- If engine fails to reignite prepare for emergency landing
- Fly the airplane
To say that EVERYONE should ALWAYS be taking off with the boost pump on is not necessarily a good thing to be preaching. There are always specific circumstances that may require individualized techniques in every situation. Risk analysis of any task should take all failings into consideration. I believe human failings should also be an important part of that analysis.
Live Long and Prosper!
Everyone that is using a Lycoming engine SHOULD be using the boost pump on takeoff. Lycoming recommends it and has published it in The
Lycoming Flyer Key Reprints (Operations).
IF you are not able to run your Lycoming Engine with the boost pump on, something is wrong and needs to be fixed before farther flight.
The following is a copy / paste from page 53 of the above link.
Use of Fuel Boost Pumps with Lycoming Engines
As an engine manufacturer, we are frequently asked about the proper use of the fuel boost pump with our power plants. Although we can?t pretend to be an expert on the fuel boost pump itself, we have some positive recommendations concerning its use with our engines. Where a boost pump is provided by the airframe manufacturer, and the airframe Pilot?s Operating Handbook has a limited treatment of the use of the fuel boost pump, perhaps this discussion can provide the necessary fuel boost pump information for the pilot in order to operate his or her
engine as safely as possible.
It is necessary to supply the engine with a steady, uninterrupted flow of fuel for all operating conditions. Entrapped air, temperature changes, pressure drops, agitation in the fuel lines and other factors affect the release of air and vapor from the fuel system. Under some circumstances where an engine-mounted fuel pump is provided, it may not be able to pump a continuous fuel supply free of excessive vapor.
An effective continuous fuel supply is provided by use of the fuel boost pump. As a general recommendation, the fuel boost pump should be used with Lycoming engines in all conditions where there is any possibility of excessive vapor formation, or when a temporary cessation of fuel flow would introduce undesirable hazards. The conditions under which Lycoming recommends operation of the fuel boost pump are as follows:
1. Every takeoff.
2. Climb after takeoff unless Pilot?s Operating Handbook says it is not necessary.
3. When switching fuel selectors from one separate fuel tank to another, the fuel boost pump should be ?on? in the new tank until the operator is assured there will be no interruption of the fuel flow.
4. Every landing approach.
5. Any time the fuel pressure is fluctuating, and the engine is affected by the fluctuation.
6. Hot weather, hot engine ground operation where fuel vapor problems cause erratic engine operation.
7. Some General Aviation aircraft require the use of the fuel boost pump during high-altitude flight. This will be spelled out in the Pilot?s Operating Handbook.
8. If the engine-mounted fuel pump fails.
If the fuel boost pump is used during ground operation, don?t fail to check the condition of the engine-mounted fuel pump before takeoff by turning the boost pump off briefly, and then back ?on? for takeoff. If the engine-mounted pump has failed, it would be safer to know that on the ground rather than in the air when the fuel boost pump is turned ?off.?
When in doubt, do the safest thing and use the fuel boost pump with Lycoming engines. Don?t be ?stingy? with the boost pump. In most cases, they last the overhaul life of the engine, and are then exchanged or overhauled themselves. AS A REMINDER, the airframe Pilot?s Operating Handbook is the authority if boost pump information is spelled out in it.
For the last 15-years, I have followed Lycoming boost pump recommendations. The only other time I use the boost pump not on Lycoming recommendation list is anytime I am below 1,000 AGL.
