The instrument-rated pilot was conducting a personal cross-county flight and was operating on an instrument flight rules flight plan.
While he was flying in visual conditions between cloud layers at 7,000′ and heading toward the destination airport, he reported to air traffic control that the Beech V35 had experienced a vacuum pump failure and that he had lost the associated gyroscopic instruments and part of the instrument panel.
He continued toward the destination airport because it had the best weather conditions compared to alternate nearby airports, however after accepting radar vectors for the GPS approach to the airport, he reported that the plane had entered instrument meteorological conditions (IMC) and that he had lost a “little bit” of control.
He then reported that more of the instruments had failed and that he was trying to get back to 7,000′.
Shortly after, the controller provided the pilot with the weather conditions at a closer airport and asked him if he would like to try to land there. However, no further communications were received from the pilot.
Review of radar data revealed that the airplane made several course and altitude deviations as it proceeded northeast until the end of the data.
The airplane was found separated in multiple pieces along a 0.4-mile-long debris path near Syosset, N.Y., with all three souls aboard dead.
Based on the radar data and debris path, it is likely that the pilot experienced spatial disorientation while maneuvering the airplane in IMC without a full instrument panel, that he subsequently lost airplane control, and that the airplane broke up in flight due to overstress during the ensuing uncontrolled descent.
Review of a vacuum pump manufacturer’s service letter (SL) revealed that the mandatory replacement time for the make and model vacuum pump was 500 aircraft hours or six years from the data of manufacture, whichever came first. Compliance with the SL was not mandatory for Part 91 operations. The vacuum pump was manufactured in May 1999, which was 17 years before the accident.
Additionally, the airplane was not equipped with a backup/standby vacuum pump.
Metallurgical examination of the vacuum pump revealed that the rotor had separated radially in numerous locations. Three vanes remained intact, and three vanes separated into numerous pieces. Rotational scoring/rubbing marks were observed on the rotor and pump housing.
Additionally, debris was noted in the inlet screen, but the engine had hit a dirt field.
It is likely the rotor’s contact with the pump housing caused the failure of the pump rotor and vanes, however it could not be ruled out that debris ingestion contributed to their failure.
The pilot had severe coronary artery disease, and toxicological testing revealed low levels of diphenhydramine, a sedating antihistamine allergy treatment and sleep aid, and zolpidem, a prescription sleep aid. However, there was no evidence that the pilot’s heart disease or sedating medications impaired his performance or incapacitated him.
Probable cause: The pilot’s loss of airplane control while operating in instrument meteorological conditions with only a partial instrument panel due to a failure of the airplane’s vacuum pump. Contributing to the accident were the pilot’s spatial disorientation and the operation of the vacuum pump beyond the six-year time limit recommended by the vacuum pump manufacturer.
NTSB Identification: ERA16FA176
This May 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.
“Vacuum pump failure fatal for three”.
I disagree. To suggest, as this headline does, that the loss of the gyro was the cause of this crash is false and misleading. The pilot failed at flying partial-panel.
GAN has a bad habit of using misleading headlines form many of these accident reports, and this is another foolish example.
Why wasn’t the vacuum pump’s age discovered during the last 11 annuals and replaced? Seems like the A&P should share the blame.
This is why self-involvement during the annual and entire ownership process is important. Joining a type club and taking part in owner-assisted annuals is a good start.
500 hour magneto checks are not required for Part 91 flying, but getting the check done should be a must do, especially for those single drive, dual mags. Some folks aren’t aware of the 500 hr check and many A&P’s don’t mention it.
A great tool for the involved aircraft owner is an Adlog aircraft record keeping system from Aerotech Publications. http://www.adlog.com
I think it is a bit revealing that after he started having control problems he reported “that more instruments had failed”. With the vacuum pump failed he would have only lost the attitude and directional gyros. If he was thinking that other instruments had failed then he was assuradly falling into the trap of following his head and not the instruments.
This one was especially painful as I am based at the same airport where this pilot was based and I saw this airplane coming and going several times.
I don’t disagree with any of the comments. However, a loss of a vacuum pump shouldn’t have ended this way. Remember, the instrument rating checkride requires a partial panel approach to the same standards as a full-panel approach, so every instrument pilot was partial-panel proficient at one time. But unfortunately, I can’t think of any procedure that is probably less likely to be practiced. Pilots have to take the responsibility to do this, as well as instructors during flight reviews.
Why try for the prime in IMC when you lose ANYTHING on the panel? Just accept the situation and go for a VFR landing alternate if it’s available.
I have my flight review pilots spend a few minutes on needle, ball and airspeed, while under the hood.
Probably all the partial panel time they will get until the “real thing”!
Sad to hear stories like this.
Until upgrades I didn’t fly much IFR in my own airplane. I was spoiled by the redundancy in the airplanes I flew professionally.
When my vacuum pump failed the old gyros were tired and needed replacing. The entire replacement cost was ~$3000 with labor, so I decided two Garmin G5’s with a GMU-11 magnetometer and a removed vacuum system would be the solution during my ADS-B installation. With the EHSI as a backup ADI and four hours of battery life in both G5’s, I have the redundancy and increased capability I need. Saved some weight, too.
I learned to fly instruments in the 70s in airplanes that were “New””, and no one seemed to be concerned about single vac systems and their risk. I never really appreciated the risk I was taking, always assuming i could fly a Partial Panel ASR approach or something. I later realized that the expense of electric instruments is something worth considering if you fly any serious single pilot IFR. Also, I installed an electric Century I simple autopilot in our C23 Beech to have a way to keep the wings level if a Vac pump blew….and it did!
As a CFII, I am very wary of any “vacuum pump” system and not willing to bet my life on even a new one.
SE IFR is a risky proposition. No ‘spare’ engine. No backup vac system. The pilot saved maybe $1,500 by running the vac pump ‘to fail’. It appears the gamble didn’t pay out like he or she hoped. Too bad two passengers shared in the consequences.