The closest kids my older brother and I had to play with growing up during WWII in Winnipeg were the Kruger brothers. They lived two houses and a vacant lot down the street from our house. There was Ron the oldest, Lloyd in the middle, and Bob at the bottom. Their father, Sam, was a vital asset in our war-rationed neighbourhood. Mr. Kruger saved our soles. He was the community shoemaker. With all the shortages, worn clothes and especially shoes were mended not thrown away.
Mr. Kruger demanded and got high scholastic achievement from his boys. As a result, both Ron and Bob became engineers and Lloyd built a successful automotive business. After the war when the huge economic boom powered by the greatest generation that ever lived overtook us, we went our separate ways. Over the years, and many moves later, I lost touch with the Kruger boys even Ron who I learned worked in the same airline as I, although I had no idea where he worked and in what capacity. Our paths never crossed.
The 727 can fly perfectly fine on two engines – right?
It was beautiful clear day in January. We were flying a Boeing 727 from Winnipeg to Toronto with a full load of southbound passengers, most of them connecting in Toronto to escape the bitter Winnipeg winter. The ride was smooth, both terminals CAVU, and a favourable wind favoured a straight out easterly departure from Winnipeg and a straight in easterly arrival to Toronto. Even the usual messed up radar vectors from Toronto Arrival Control would not ruin our early arrival.
A few minutes after reaching TOC at FL330 and setting cruise power, the oil filter bypass/low oil pressure amber light for the number three engine on the front panel came on. A quick check of the second officer’s panel revealed oil pressure and temperature were normal. The QRH (Quick Reference Handbook) mandated reducing power on the affected engine. However, if the front caution light went out and the S/O panel indications remained normal, then the engine could be kept running at reduced power to meet the demands of the electrical and pressurization systems. Buried within the wordy QRH was the need to press to test the bypass warning light on the front panel for brightness. In other words, the light had a dual purpose and dual brightness function.
We discussed our options and agreed to keep the engine running at whatever power kept the light out as long as pressure and temperature remained normal. The alternative meant shutting down the engine and returning to Winnipeg. That meant inconvenience and aggravation for our connecting passengers, not to mention cost considerations for the airline. But something about the complicated QRH procedure left me feeling uncomfortable. We decided to seek further advice and called Maintenance Central in Montreal on the company frequency. We told them our problem, actions and plans and asked them if our actions would cause any damage to the engine. They replied that we had interpreted the procedure correctly.
Feeling good about our decision, we continued with the number three engine just above idle keeping all the a/c systems running normally. We had no trouble maintaining FL330 with only a slight reduction of airspeed. We would still arrive early, all our passengers would be happy and the company would save the cost of the associated delayed connections. For weeks, I wore a smug smile on my face as I told my colleagues what a wonderful job I had done.
Then one day I learned the whereabouts of one of my boyhood pals. I opened my company mailbox to find an envelope containing a curt note from the manager of the company Pratt & Whitney overhaul department. It read:
Captain Jim:
We found a little problem after tearing down the number three engine on a/c number 413 that you brought in from Winnipeg on flight 190 January 15th. The engine was starved of oil. If the engine had continued running for fifteen minutes longer, it would have catastrophically self-destructed.
Just thought you’d like to know.
Regards:
Ron Kruger
Manager PW JT8D Engine Overhaul Montreal
What do those oil pressure lights really mean?
As a career-long Boeing enthusiast, I found the 727 oil filter bypass warning system counter intuitive to the typical uncomplicated engineering of both Pratt and Whitney and Boeing. I lost trust in our airline’s Maintenance Central and Flight Operations Department and the quality of their 727 QRH write up. Buried deep in the procedure – not highlighted in any way – was a statement to use the procedure only if one engine was already shut down as a means to keep electrics and pressurization operating. That statement should have been in a large bold font at the very beginning of the procedure.
Above all was my regret over not exercising proper good judgment by not interpreting the QRH procedure with the due diligence it deserved. The possibility that I might have caused a disaster left me shaken to the core and prompted me to do some serious soul searching about my professionalism.
I thoroughly enjoyed my 13 years flying the 727, thinking that it was completely devoid of any bad habits or engineering flaws. Compared to other airplanes, it seems nit-picky to point out this one small but potentially dangerous flaw in an otherwise great machine. In spite of some interesting management shuffles, our airline is a great airline and I’m proud to have been part of the team. To me it was the range of experience, age and camaraderie of the three-person crew on the 727 that made my time on it so enjoyable.
Epilogue
Explanation of our company’s fix on the original Boeing AOM re: oil filter by-pass W/L:
Insert 192 (Low Oil Pressure Or Filter Bypass Light – Modification) was issued 21 Jan 81 and the technical explanation of the insert was: “A modification will be carried out to make the intensity of the light different for each function. A resistor will be installed in the Low Oil Pressure switch line and it will therefore not provide as bright a light as will the Filter Bypass Switch. To know which brightness you have, press to test. The Filter Bypass will be the same as the test. Low Oil Pressure will be dimmer.”
- 15 minutes to disaster – and I never knew it - October 26, 2017
- Dozing for dollars at 39,000 feet - August 23, 2017
- Grounded at 37,000 feet - November 16, 2016
I wouldn’t take the “15 minutes” part too literally—it’s just the kind of thing professionals say to laypeople to emphasise their point, like when doctors tell someone she would have died if she’d waited an hour longer to come to the hospital. What they really mean is just that the failure was high-risk/imminent, but giving a made-up exact time helps avoid a barrage of follow-up questions and has a bigger emotional impact.
And agreed, it was a badly-written procedure. I would put the primary responsibility in this case on the technical writers and editors, not on the crew trying to digest information quickly in a busy operational environment. Even you airline pilots don’t have to be supermen/women (at least not all the time).
I felt bad on two levels. The first I explained in the article but the second perhaps that should have been more important to me was I had made no effort to keep in touch with my boyhood pals especially one in the same industry and further I made no attempt to contact him after the incident. I guess it might have been shame.
Jim G.
Great write up Jim. I had a similar soul search after departing overseas stn with one thrust-reverser on MEL (inop and lock wired). After engine start we got an amber T/R light on the good engine. Communication with mtce was only through datalink but we could talk directly with the local station engineer for line mtce (who thankfully was an Aussie!)
He said leave the engines running and he would do a physical check on the engine and reverser. All sounded pretty logical. He came out and we cycled the T/R several times and the light never came on again. He signed it off as serviceable.
A week or so after I got home I got the dreaded call from the Chief Pilot. He said they had reviewed the incident and we should never have departed under the circumstances. Quite disconcerting after the fact. I made the case that all the information we had in the manual and from mtce did not prohibit departure.
He said there were people who should have known and should have intervened but the station and the hour (0300 local at home) meant that the info wasn’t passed along.
Fortunately there was no harm done but I can relate to the feeling of soul-searching.
Interesting in the follow up that nothing changed from the pilots point of view regarding procedures and manuals.
Cheers RM
I was a 727 Captain for Laker Airways Limited and also a pilot for Braniff International and Bahamasair on the 727. We had the same procedure in all of our manuals and I do not remember that caveat only continuing to operate the engine only if one other engine was already shut down. Interesting about the low oil pressure lite being dimned.
Capt Jim,
Ten years spread over the three seats in the 727, exactly the same scenario except our pressure light came back on after a few minutes at reduced power. Per our company QRH, we shut down number three. Flew great and the passengers didn’t know we’d shut down the engine.
Don’t beat yourself up. If not for our filter bypass situation causing the light to reilluminate we’d have done the same thing. That note was too easy to miss.
Capt Ron
Jim, What I get out of your very salient story and the majority of the responses to it upntonthis point is that a very strong mission focus in the airline culture existed (and probably still does), and it included at least some members of your maintenance team. So, using the information you provided, what were the ‘best’ and ‘worst’ outcomes? Best = early or on time arrival. Worst = catastrophic failure and a serious emergency situation to deal with. Evidently the cultures of your airline and of the other pilots who have commented so far at least tacitly minimize risks of failure and maximizes mission accomplisment. FWIW, if NTSB accident reports accurately portray risk preferences, this mindset remains problematic among GA pilots and at least some professional crews. Thanks forva very valuable glimpse into past and present risk preferences.
Hi Jim,
I flew the 727 for 17 years as a F/E and an F/O. I saw many irregulars and a few more serious things. None of which I considered life threatening. (Except for that wind shear we encountered in DEN one day. But that’s another story for another time). You did the right thing and shouldn’t second guess your actions. Your Maintenance friend should never make guesses about what MIGHT have happened. It didn’t happen and you landed safely. End of story. Good job as far as I am concerned.
Bob Retired United Pilot