727 Early high sink rate crashes

[Robert Campbell]

727 Crosswind Landings

Yes, the 727 did not like any crab on a crosswind landing. Being an old taildragger (conventional gear, not tail strikes) pilot from day one, it was very comfortable to watch an approach and landing with the wing down/top rudder technique.

I never flew one, but I rode jump a few times.

No engines below the wings made it possible to land with a significant bank unlike the 73s, 4s, 5s, 6s, 7, and ABs. Actually, a one (two) wheel landing in gusting conditions was a lot of fun.

[lederhosen]

I remember sitting down the back on a gusty 727 crosswind landing in Brisbane and experiencing exactly what happens when you get it wrong. It was back in the good old days and after what felt like the third bounce, as we taxied rather carefully back to the terminal, the Captain came on the PA and said, I quote: 'Sorry about that ladies and gentlemen, that was the co-pilot, we have to teach them some time.'

I think we can all agree that even if not gospel, Les Morgan was one of the greatest ever aviation writers.

[hetfield]

but many folks think the 727 was the nicest flying airliner ever built.

Yes, it's (was) a pilot's plane.

[The late XV105]

Twas a DC-9 Tyres. Couldn't find the video on the web I'm afraid.

That'll be because to be pedantic it was an MD80 as correctly mentioned by WHBM

Going to Youtube and searching for MD80 landing returned the video in question:
YouTube - MD80 Landing Crash

Not surprised nobody wanted the repaired hull!

XV105

[Captain104]

@Hetfield

IMHO, most airlines didn't order them at all. E.G. LH had only four out of 35 or so equipped with NLG Brakes. To my knowledge, they never ever had been used......

Sorry. Different opinion: During 1983 and 1990, the LH fleet of B-727(FRA NG + Condor) operated with nice working nose wheel brakes. Acc. LH Flight Crew Training manual 727(dated 20th Jan 1988). Limits: speed greater than 15 kts, turned out of center not more than 5,5° and Antiskid on.

Otherwise fully agree: a pilots dream. You could sink like hell with increasing speed, or sink and slow down at the same time. Use of gear as speed brake could do wonder.
No 1 and 3 idle, No 2 about 55% N1 with small corrections and your 727 followed you in an approach down to final config. like a well educated Lady.

To watch: as mentioned before, a pretty long distance between CG and MLG. TO rotation with a short "delay" at 9,5°. No Flaps 40 in turbulence or strong crosswinds.
During flare, a slight dip left or right with a titty of power did the grease for me. Others did a grease job by "releasing" the stick a bit forward.

The are 2 AC's I dream of ( out of 12 types mil+civ) and wake up in the morning with a happy smile on my face. No 1 Boing 727, No 2 T-38 Talon.

Regards

[hetfield]

Limits: speed greater than 15 kts, turned out of center more than 5,5° and Antiskid on.

@Captain104

To activate the NLG brakes you had to press the pedal to the metal. Me thinks those planes had been sold after many years still with the origin NLG brakes. Never ever felt any temperature rise on the iron even after heavy braking.

kind regards

[RWEDAREYET]

I think the primary reason for flaps 30 landings was fuel consumption. Less noise and less chance of excessive sink rate was just an added benefit. Many operators are asking the pilots to use flaps three on the Airbus 320 family for landing these days. This is for one reason only and this is fuel conservation. If I remember correctly, was a long time ago, I think gas prices spiked in the 70's much like they are now 30+ years later. This may have been one of the primary factors.Granted the CRJ's and the ERJ's have T-tails, but that is the only similiarity to the old Boeing. The wings are completely different. The sweep on a 727 is much like a fighter jet and the sweep on a RJ is more like a prop aircraft. The wing is why a high sink rate could sneak up on you. Hence the terms energy management, spooled and stable came about. I miss the old girl, still my favorite to fly.

[wileydog3]

Did you fly the early KC-135 with the old engines that had water on takeoff? How much thrust did those engines have...both with and without
water?

Yes. I got on the 'water wagon' in 1970 after returning from Vietnam flying 0-2s as a FAC. ??? The J-57 put out an astonishing 12845lbs thrust dry and using the 5600lbs of water (in 2 minutes) pushed it up another 100lbs. That is the Dash 1 numbers and it never made any sense because the difference between a 'dry' and 'wet' takeoff was very noticeable. And even more noticeable if you lost water on a pair of engines.

When I got on tankers, it had just changed from LEFT/RIGHT water injection to INB/OUTB. Needless to say, one has to wonder how long that problem existed before someone figured out the solution to some real asymetric thrust problems. And the only powered control surface on the Boeing 717 (real one) was the powered rudder.

It's my understanding that the max takeoff weight for the 135 (under war time conditions) was 300,000 lbs. Is that correct?

Max taxi was 301,500 with max takeoff at 297,000. Out of Thailand for the fighter refuelings our usual configuration was '165 wet'. (110k empty gross, 5600lbs water, 165,000 fuel for a takeoff weight of around 280. With little more than 50,000lbs of thrust, you can see the takeoffs were always somewhat exciting. At 280k, the Vr would be around 180kts.

Just want to calculate the thrust to weight is with one engine inopt. I heard the plane, at 300,000 lbs, didn't fly too well with one engine inopt.

We had an 'S1' instead of a V1 but it was essentially the same. Never lost one below S1 but did lose one after S1 and it was just another Boeing. And like other Boeings, the magic number was 210kts. Get 210kts and clean, you are home free.

I had the privilege of going to the Instructor school at Castle in Merced. We really got to play with the machine doing lazy 8s (as much as one can in a KC-135) with a B-52 on the boom; 3, 2 and single engine approaches with missed approach (yes, below 170,000lbs you could fly a single engine approach but the go-around was very interesting and you used a fair amount of the 200ft from the CatI mins).

When I was assigned the tanker, I was quite upset. I had done a tour and had been promised fighters. I figured any machine with more than one engine and more than one engine had a basic design flaw. My ops officer, a grand fellow, pulled me aside and told me the tanker was a great design and to prove his point he asked me to go find another airplane that would lift approx twice its empty gross weight, would do 0.90M all day, had a ceiling (which I took it to) of 42,000ft (oxygen mask limit.. not airplane), had legs to cruise to Europe or throughout the Pacific and where you could still smoke and have a good cup of coffee (pre-Starbucks and before no-smoking regs).

I still check tail numbers when I see a re-engined tanker. Hard to believe something I flew almost 40yrs ago is still doing the job.

now back to our regularly scheduled thread..

[PantLoad]

Thanks

As always, wileydog3, your posts are quite interesting. Thank you for the answer to my questions.


PantLoad

[org]

I guess I'm pretty lucky to be flying the 727 (again) and in a place we can really take advantage of the airplane's ability to maneuver and descend.

We quite often approach from directly over the airport at 7000 to 10000 feet and spiral down staying within about 3 miles from the threshold. At anything less than 8000 ft it can be done in one turn no problem with idle thrust, flaps 25 and gear up until on the base turn. Carry a little extra speed so the sink doesn't develop, then spool it up and curve to the final. Obviously not a pax operation.

The lack of pitch and yaw response to power changes makes it a dream to fly compared to aircraft with underwing mounted engines, and except for the landings, it's almost possible to "think" it around. A great combination of maneuverability and stability.

[misd-agin]

Captain 104 - "The are 2 AC's I dream of ( out of 12 types mil+civ) and wake up in the morning with a happy smile on my face. No 1 Boing 727, No 2 T-38 Talon."

*********************************************************

I was thinking of the T-38 also. Guys would say "it's hard to land" etc, etc. Once you figure it out it was a wonderful flying airplane. Some guys never figured it out and some even quit the program when they could not overcome their fear of the T-38.

727 was easier to figure out.

757's make me smile also. Especially rocketing out of small fields or mountain airports. Nothing like 22-23 degree pitch attitudes on departure.

[wileydog3]

Glad to help...

[wileydog3]

I was thinking of the T-38 also. Guys would say "it's hard to land" etc, etc. Once you figure it out it was a wonderful flying airplane. Some guys never figured it out and some even quit the program when they could not overcome their fear of the T-38.

I always thought the -38, the Lear 23 and the 727 were similar in that when you pulled off power, the nose rose slightly. IF you held what you had when the nose came up, it worked out nicely. IF you let the nose move or fall through, it was going to be a firm landing.

Maybe the others did it too but I could hear when the tanker went into ground effect. the sound of the engines changed due to the ground effect and you could literally when you got close to the runway. Probably can't hear it now...

Of all the airplanes I have had the privilege to fly still the most challenging to consistently land good is my 1946 Swift. That little rascal just keeps coming after you and with gusty crosswinds, it focuses my attention like no other airplane. And yes, I know some guys think it is just a sweetheart but with a 90deg cross with 10 gusting to 18kts, it gets my full attention.

The 757/767 were just fat 737s... wake me up after touchdown. I understand the -800 has some tendencies that require a deft touch but the I only did the -200/-300 and -400.

[Captain104]

@ misd-agin

I was thinking of the T-38 also. Guys would say "it's hard to land" etc, etc. Once you figure it out it was a wonderful flying airplane. Some guys never figured it out and some even quit the program when they could not overcome their fear of the T-38.

You hit the nail and must be an insider. Transition from T-37 to T-38 in Williams AFB was critical for some fellows, they had to quit. I remember also the hour required to get used to the "hypersensitive" stick while flying formation. Could you believe: 4 ship formation acro over Arizona! For me, this bird seemed tailored and after the first TO ( 2 instant AB) I decided (even as naval career officer) to fly for all my lifetime- if possible.

Sorry, back to thread. As org and others could understand, the B-727 IMHO is/was the civilian counterpart. Sounds crazy: both aircraft with a kind of soul?!

Regards

[767skydriver]

Agreed

I have flown those three aircraft, and you could not be more correct.
Good comment.'

[Tee Emm]

As I recall, as you came across the fence, you eased back on the yoke slightly...as doing so, increasing thrust slightly. Then, as nearing the runway, we relaxed the back pressure...perhaps even pushing a bit on the yoke...and perhaps increasing just a bit more thrust. Such technique resulted on rolling it on at Vref +5 to Vref +10 or so.

I have not flown a 727 so cannot comment with authority on the burst of power technique mentioned. But many times in flying the 737 series I have seen pilots flying a perfectly stable approach and as they flared they would quickly advance the thrust levers a couple of inches giving a burst of power then just as quickly close the thrust levers. It made no difference to the landing impact but merely extended the touch down point.

When questioned about this "technique" they said the burst of power helped cushion the flare. Maybe they had flown the 727 in another life? I was mystified by this nonsense and suggested they were wasting their time since all it did was to increase the float because of the extra speed - which in turn caused the aircraft to land further into the field.

In the 737 it a completely unnecessary maneuver and was often done as a old wives habit. This burst of power at the flare is occasionally seen in the simulator and it is hard to convince some pilots that they are fooling themselves.

One explanation of some of the early spate of 727 high sink rate accidents was the fact that in the airline seniority number system in USA,when a new type was introduced, the unions insisted that the most senior pilots get first crack at the new type. This was because of company and union seniority that also gave them the increased salary associated with any new type.

In those days, most of the older pilots with their high seniority number were previously captains on heavy piston engine airliners like the DC6, DC-3, Stratoliners, Constellations and similar. In other words the cream of the old big radial engines era. These pilots with their thousands of hours on relatively benign aircraft with big propellers, would have run into great difficulty learning an entirely new engine handling technique on jet turbines.

Closing the throttles towards idle on a large piston engine aircraft at 100 feet or higher above the runway, especially with extra speed in hand, would pose no serious danger of high sink rate and loss of energy in a DC-6. Try that in a 727 and a heavy landing was assured. The relatively slow spool up times from closed throttle setting of the early JT8D engines would have caught many senior pilots by surprise.

The danger was the older (seniority reigns supreme, remember) captains of that era would instinctively revert to piston engine throttle handling if high or unstable on late final and reduce thrust far too much for safety in the 727. By then a high sink rate would occur and with no prop blast over the wings to increase lift, the 727 was simply smash into the runway while the engines were spooling up.

A similar type of problem exists today when some older captains convert from well known jet transports like the 737 to the sophisticated flight management and fly by wire operation of the Airbus A320. Some are unable to learn the completely new concept of button pushing since the A320 and similar are automatic pilot dependent from lift off to short final. The actual flying of the side-stick aircraft is easy but the learning experience on highly technical flight management systems can have an overwhelming effect on otherwise highly experienced pilots. So they fail to complete the simulator training.

[con-pilot]

I instructed on this one for 18 years and never saw the 'aircraft develop' an excessive sink rate, only the pilot

And there be the real truth.

[Sir George Cayley]

But why did crew allow such a departure from the existing sink rate?

Could the reason why Precision Approach Path Indicators were developed have anything to do with it? If you are old enough to remember T-VASIS that were around when ILS and the Jet Age started, you may recall that high sink rates were a problem with T-VASIS when coupled with prop pilots converting to turbo jets.

Worth delving into the archives I think.

SGC

[Spotlight]

Tee Emm

Not necessarily to disagree, but to hopefully contribute. The burst of power in the flare can be helpful when landing an 800 in gusty conditions. This aeroplane can be unforgiving if in the flare airspeed is trending backwards below Vref.

If encountering localised and difficult conditions. e.g funnel effects when the approach is between hills, water to land, or the tree line starts at the threshold of a runway that is sunken at the end you are using. The burst and chop does help.

On a stable approach on a Wing Commanders day in the 737-800 a trickle of power coming on in the attitude check to hold Vref +5 to ten feet rolls it on every time.

Perhaps you have been finding guys that are reflexive. Flying's not that easy!

[Tee Emm]

This aeroplane can be unforgiving if in the flare airspeed is trending backwards below Vref.

Of course you are quite right and that applies to most jet transports. The key is not to reduce to idle until into the flare manoeuvre. The "burst" of power is only if a sudden unexpected sink occurs -not because you are slower than you should be at the flare. In the Pacific island atolls where coconut palm trees often surrounded the airstrip it was common to experience significant crosswind windshear at 50 feet below tree level. The runways were short and when coral is wet the touchdown had to be precise and smack on the 1000 ft marker. A wise pilot never cut the power until the first back movement of the flare maneuvre and then cut it quickly as the residual thrust from a spooling down engine could often carry the 737 deeper into the field than desirable.

What I am trying to say and not very well, is the burst of power technique was only used as a last resort if things went ape and the aircraft was dropping out of the sky. It was never meant as a planned specific landing technique for a normal stable approach and landing. If it was, then Boeing would surely have mentioned this under their landing guidelines in the FCTM. There were pilots that gave a burst of power at the flare for every landing because they thought it was a Good Thing. I have watched first officers do a perfectly good approach and just as they flared a twitchy captain would shove open the throttles and back again leaving the first officer wondering what the hell the captain was doing to him.