The private pilot was flying over the ocean and just off the coast of Miami when an air traffic controller asked him to descend to 500′.
He reduced power and applied carburetor heat until he reached the assigned altitude. He then attempted to increase engine power and level off, however, even with the throttle full forward, the engine power remained at its previous setting.
The pilot attempted to resolve the situation, but he was unable to maintain altitude and ditched the airplane in the ocean.
Although weather conditions were conducive to serious icing at glide power, the pilot had applied carburetor heat during the descent, which should have melted any carburetor ice during the descent.
A post-accident examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. The cause for the partial loss of engine power could not be determined.
Probable cause: A partial loss of engine power for reasons that could not be determined.
NTSB Identification: ERA16LA103
This February 2016 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
Recently , had my engine on a 182 quit after landing the night before the temps were 6 degrees . At take off time outside was 30 degrees . I had applied heat to the bottom cow opening for 20 mins and drain all three sumps before take off . Run up good but a little rough at Idle . Latter after one leg of flight that day the plane sat in full sun and 25 gal of fuel added to fill 92 total ,problem gone . I assume ice crystals suspended in the fuel clogging the fuel screener .
On short final till 1/4 mile out had carb heat on and leaned then , off or in . I have 2,000 hrs in the plane , 60 hour zero hr remain engine and electronic ignition one one set of plugs .
Any one with similar experience more reasoning to the problemish
A scary scenario for sure. There’s always a bit of trepidation when the power is reduced not knowing if it will recover. Good for him that he used carb heat. I wonder about the power and mixture technique. It appears the runup indicated some spark plug fouling already existed. That’s pretty common as many pilots don’t lean during the taxi or the flight. If during that descent, the power were reduced substantially, and the mixture were left or put at rich, and with carb heat which enrichens the mixture even more, then that may have had a substantial impact on the proper firing of the spark plugs which were already showing signs of fouling. Low power, rich mixture, and carb heat combine to create the worst condition for fouling spark plugs. I guess no one will ever know for sure. For enroute descents I think it’s better to make small power reductions and keep it leaned per recommended cruise setting. If carb heat is needed, a little more leaning may be necessary.
The accident report and supporting documents all say the pilot ‘reduced power and [then??] added carb heat…” If he added carb heat after the power reduction it’s likely it was too little heat, too late to counter the high potential for ice. A lot of times the order we do things in the cockpit is just as important as the thing we just did (too late to be effective).
Well we don’t know it was only carb ice – the spark plugs according to the report were fouled at runup. I had a carb ice event enroute and carb heat cleared the problem in seconds (in a Grumman American trainer). It wasn’t after a reduction of power, but I don’t think that would have made any difference. A Piper-28-161 POH I found online indicates for a normal descent, “The throttle should be set for 2500 rpm, mixture full rich and maintain an airspeed of 126 KIAS. If carburetor ice is encountered apply full carburetor heat”. That would indicate carb heat should be effective even if applied after the power reduction. But on the other hand, if a prolonged power off descent is to be made (not the situation here I don’t think), and icing conditions are suspected, it is recommended that the pilot “apply full carburetor heat prior to power reduction”. It goes on to say mixture control should be leaned as required. That’s an item that’s suspicious to me – I’ve seen too many pilots just leave the mixture full rich throughout the flight which is likely to foul the spark plugs.
I’m guessing improper use of carburetor heat.
The short narrative did not say from which altitude the pilot descended. During prolonged descents with low power the carb heat loses effect gradually as the engine cools down, and the engine starts building carb ice despite full carb heat being applied. Accidents like this has happened because of that, and there is a warning in the Pilot’s Manual (at least for some models) about this.
Kudos to the pilot for a successful ditching. Also kudos for his decision to ditch than make a beach landing and risk injury to persons there. See the NTSB Docket for a brief discussion of this excellent pilot decision. I wish more pilots would follow his example of concern for others.