Posts by user "fdr" [Posts: 31 Total up-votes: 151 Page: 2 of 2]¶

That mid airs happen, there is data, true
That there is adequate data of American airlines running into military helicopters in the terminal area? We have one data point. That is an exception event. The near misses, there is more data, but apparently not enough to get anyone's attention before a bad day out occurred (whether DEI dependent or not)

The intent of a safety system is to tend towards improved safety. To do so, it needs data to make rational assessments, and we have a system today that is based on responses to exceptions, and often responses to exceptions that arose due to responses to other exceptions, etc. We have a stack of bandaids that are our rules and regs, and they act as soporifics, great if you are suffering from insomnia.

As a system, it sucks.


TCAS RA have inhibits at low altitude, or do you have some other system in mind?

As a TCAS II owner, please don't change TCAS, change the flight paths. Every time we change TCAS version, Honeywell gets a boost to their bottom line. Honeywell is the company that makes Boeing look great.

Going from TCAS II Change 7.0 to 7.1/7.1a was a simple matter of handing over enough cash to buy a couple of Porsches, for the new computer to effect a simple software change. What is irritating is the change was not an enhancement of the system it had all the hallmarks of incorporating the standard for TCAS at the time. An iPad with Foreflight or Garmin pilot an ADSB-in input is frankly more value when operating in the weeds, While we are at it, it is remarkable that Garmin Pilot and Foreflight provide better obstacle alerting than the certified EGPWS system does.

There is very little translation of the target aspect in a mid air collision. The Left turn of the CRJ would have put the 60 low down in the RH side window of the CRJ, away from the direction the aircraft was turning. The 60 was below the horizon all the time, from the CRJs perspective, and the 60s fuselage has also passed under the CRJs fuselage at impact.

Ours didn't either. The CRJ has mandated reqts.

R-22 v UH-60L/MH-60 etc.. yes they are absolutely different, have different paint n everything, different spelling and all. The relationship of inertial vs aerodynamic forces on the rotor system. generally referred to as the Lock number are worlds apart. It may seem like a meaningless number but it is what gives the characteristics of the harmonic control that you, the rotary pilot are actually controlling. It also uses similar factors that determine the tip path plane of the rotor for different conditions and the relationship between control input, swash plate plane and the tip path plane of the rotor.

During a quick stop, your instructor was correct to prepare you for what follows rapidly thereafter with respect to your heading and your need to be ready for some footwork, and to be aware of the torque demand that follows where the wake influences your aircraft. This isn't however vortex ring state, nor is it settling with power, it is a transient related to your wake. The R-22 has adequate but not fantastic tail rotor authority, the UH-60 has an excellent tail rotor befitting a damned fine tactical/combat helicopter.

You can get through a complete aviation career in helicopters without opening up any books beyond your training manuals. Helicopters also bite back hard if you.step out of line, so my suggestion is that you may frame Torquetalk's comment: “you don’t know what you don’t know” , and enjoy reading about your machines physics.

Suspect the 2nd to last position given has errors.

Long answer? No.

Short Answer? "__"

The NW wind results in their CAS being lower if maintaining a desired ground speed, and as LW50 and John Dixson would attest to, the crew would be aiming at generally maintaining speed above ETL, to improve ride and economy, noise, pretty much everything. Civil helos will normally specify a minimum IFR speed to keep tracking tasks of the pilot to a manageable level. The crew in this case are night, VFR, but without SAS or ALTHOLD, helos are a bit more demanding than fixed wing. Flying these helos down in the weeds is why Pilots like Lonewolf and John D got paid the big money and have such extravagant retirement life as of course their Government respects their service that much.

CG, (& LW), thanks for cutting through the noise.

There is graphic evidence that the fuselage of the 60 went under the nose of the CRJ700, and they hit is probably established beyond reasonable doubt on this forum, if not in the evidence of the wreckage in the Potomac. The flight path of the CRJ is well established, up until the moment that the aircraft struck. That should itself have put to bed the matter of height in the analysis.

It is highly probable that the 60 was on altitude on their instruments, and the causal factor being misidentification of a visual target beyond 5nm at night, landing on RWY01, while the CRJ is not pointing at the helicopter, it is presenting the red navlight on the port wingtip to the helicopter drivers, along with occasional strobes against a night sky. The vector of the CRJ across the visual sector of the helo crews was a slow translation to the right, and then from off around 10 o'clock the CRJ intersects the RWY33 finals and becomes a stationary target well off the main scan of the helicopter crew. When asked to confirm they are passing behind the CRJ traffic, they have the RWY01 traffic off to their right, and they are reasonably expecting that to be their traffic. If they don't have a breadcrumb trace of the traffic on their ND of tac display, while the outcome is unfortunate, I would argue that misidentification of a target in a condition where misidentification is a high probability is not the primary causal factor, it is a consequence of the practice of mixing crossing LL traffic with landing and TO traffic.

My concerns are not future risk from this condition occurring, failure to place spak filler over the cracks in this practice would be naughty. My concern is the system scapegoating a US Army flight crew doing a task that is arguably unreasonable. The fact that some may consider it just normal practice done badly does not answer the fact that physiological limitations and the kinetics of this situation make a mid air a near certainty, the obvious evidence being they did hit, the day before there was a near-miss/loss of separation.

It is time for command to assume responsibilities that go with their post, and not blame those beneath them that travel in harms way on the implicit faith that command is competent and cares for the crews safety, and the national resource that they represent. To do otherwise is conduct unbecoming.

The CRJ crew were having a normal day, until they were killed. The passengers on board could also reasonably expect that our industry cares enough to actually do what we say we are doing, and to MANAGE SAFETY , if that is not too much to ask for. Managing safety does not equate to box ticking, it is the very fact we have devolved into considering safety in a stochastic system to be assured by compliance that we get to this sorry saga.

Point taken, if the crew were flying a RADALT rather than a BARO. That would give a correction to their altitude of.... 10 ft, at the maximum, that being the elevation of the RWY33 approach end. The Potomac has a fall gradient which indicates the end of the runway is around 4 ft above MSL, which would give the error in RADALT to BARO. If the end of the runway is at water level, then it's 10 ft.

OTOH, the CRJ is not flying a BARO ALT, it is descending on a visual glide slope that would approximate something near 3 degree, 5.2%, from whatever aiming point they had chosen, +/- the vertical error from that ideal glide slope. They stuck each other with the UH60 striking from below. John D and LW50 can suggest the static system error that is in the -1 for the UH60L, I don't have the FM for that type. The static pressure ports are on the 2 pitot static heads that are above the cockpit area, just behind the rear edge on the pilots doors. For the UH60A,
.

...so for the A model, the drivers get raw static for their ALT displays. Later models with EFIS systems would take the same data and process that from analog to digital, and that would normally be done by an ADC system, which can remove the errors that arise from direct static sources with some rat cunning. For our jets, the ADC data does not correct all static errors, that is why we generally see a negative transient of altitude and VS rate at rotate, the flow conditions around the static ports are changing. The helicopter has the static ports in the wake of the rotor, which alters with CT, and with J so pretty much is a mess for getting nice n' tidy accurate pressure altitude displayed. The RADALT is better, it is subject to errors as well due to attitude changes but they are generally tolerable by the choice of the fan shape of the transmitter. Bottom line is, assuming that the aircraft should have missed by a hair vertically given the wide range of errors that would apply to the helicopter instruments is immaterial to the fact that they were otherwise going to be in a grossly unacceptable vertical separation in any circumstance. That they arrived at the same place in space and time is a consequence of a very straight forward error of identification of a single target when confronted with multiple targets, which we have known to be an issue for about a century. Hard to blame the PF in getting caught out doing a practice that is known to be hazardous but which is institutionally tolerated as "business as usual".

Not unless ATC have appended their instructions with that as a route limitation.